feat: implement comprehensive configuration management

- Centralize 45 scattered pub const values from 13 contract modules
  into contracts/teachlink/src/config.rs (15 sections, fully documented)
- Each module re-exports its constants from config via pub use aliases
  preserving backward compatibility
- Add mod config to lib.rs
- Add indexer ConfigManager: typed IndexerConfig snapshot, startup
  validation (URL format, port range, poll interval, batch size),
  hot-reload via reload() method
- Add AppConfigModule wrapping NestJS ConfigModule + ConfigManager
- Add GET /analytics/config and POST /analytics/config/reload endpoints
- Wire AppConfigModule into AppModule and ReportingModule

Author: Mrchinedum

contracts/teachlink/src/analytics.rs

@@ -8,8 +8,8 @@ use crate::storage::{BRIDGE_METRICS, CHAIN_METRICS, DAILY_VOLUMES};
 use crate::types::{BridgeMetrics, ChainMetrics};
 use soroban_sdk::{Address, Bytes, Env, Map, Vec};
 
-/// Metrics update interval (1 hour)
-pub const METRICS_UPDATE_INTERVAL: u64 = 3_600;
+/// Metrics update interval — re-exported from config for backward compatibility.
+pub use crate::config::METRICS_UPDATE_INTERVAL;
 
 /// Analytics Manager
 pub struct AnalyticsManager;

contracts/teachlink/src/atomic_swap.rs

@@ -10,14 +10,12 @@ use crate::storage::{ATOMIC_SWAPS, SWAP_COUNTER, SWAP_GUARD, SWAP_TIMELOCK_SEQ};
 use crate::types::{AtomicSwap, SwapStatus};
 use soroban_sdk::{symbol_short, vec, Address, Bytes, Env, IntoVal, Map, Vec};
 
-/// Minimum timelock duration (1 hour)
-pub const MIN_TIMELOCK: u64 = 3_600;
-
-/// Maximum timelock duration (7 days)
-pub const MAX_TIMELOCK: u64 = 604_800;
-
-/// Hash length (32 bytes for SHA256)
-pub const HASH_LENGTH: u32 = 32;
+/// Minimum timelock duration — re-exported from config.
+pub use crate::config::SWAP_MIN_TIMELOCK as MIN_TIMELOCK;
+/// Maximum timelock duration — re-exported from config.
+pub use crate::config::SWAP_MAX_TIMELOCK as MAX_TIMELOCK;
+/// Required hash length — re-exported from config.
+pub use crate::config::SWAP_HASH_LENGTH as HASH_LENGTH;
 
 /// Atomic Swap Manager
 pub struct AtomicSwapManager;

contracts/teachlink/src/audit.rs

@@ -9,11 +9,10 @@ use crate::storage::{AUDIT_COUNTER, AUDIT_RECORDS, COMPLIANCE_REPORTS};
 use crate::types::{AuditRecord, ComplianceReport, OperationType};
 use soroban_sdk::{Address, Bytes, Env, Map, Vec};
 
-/// Maximum audit records to store
-pub const MAX_AUDIT_RECORDS: u64 = 100_000;
-
-/// Compliance report period (7 days)
-pub const COMPLIANCE_PERIOD: u64 = 604_800;
+/// Maximum audit records to store — re-exported from config.
+pub use crate::config::AUDIT_MAX_RECORDS as MAX_AUDIT_RECORDS;
+/// Compliance report period — re-exported from config.
+pub use crate::config::AUDIT_COMPLIANCE_PERIOD as COMPLIANCE_PERIOD;
 
 /// Audit Manager
 pub struct AuditManager;

contracts/teachlink/src/bft_consensus.rs

@@ -17,20 +17,14 @@ use crate::types::{
 };
 use soroban_sdk::{Address, Env, Map, Vec};
 
-/// Minimum stake required to become a validator
-pub const MIN_VALIDATOR_STAKE: i128 = 100_000_000; // 100 tokens with 6 decimals
-
-/// Proposal timeout in seconds (24 hours)
-pub const PROPOSAL_TIMEOUT: u64 = 86_400;
-
-/// Number of consensus rounds per rotation epoch.
-/// After this many rounds, the active validator set is re-evaluated and
-/// low-reputation validators may be rotated out.
-pub const ROTATION_EPOCH_ROUNDS: u64 = 100;
-
-/// Minimum reputation score required to remain in the active validator set.
-/// Validators below this threshold are rotated out during epoch transitions.
-pub const MIN_ACTIVE_REPUTATION: u32 = 40;
+/// Minimum stake required to become a validator — re-exported from config.
+pub use crate::config::BFT_MIN_VALIDATOR_STAKE as MIN_VALIDATOR_STAKE;
+/// Proposal timeout — re-exported from config.
+pub use crate::config::BFT_PROPOSAL_TIMEOUT as PROPOSAL_TIMEOUT;
+/// Rotation epoch rounds — re-exported from config.
+pub use crate::config::BFT_ROTATION_EPOCH_ROUNDS as ROTATION_EPOCH_ROUNDS;
+/// Minimum active reputation — re-exported from config.
+pub use crate::config::BFT_MIN_ACTIVE_REPUTATION as MIN_ACTIVE_REPUTATION;
 
 /// BFT Consensus Manager
 pub struct BFTConsensus;

contracts/teachlink/src/config.rs

@@ -0,0 +1,184 @@
+//! Centralized configuration for the TeachLink contract.
+//!
+//! All tunable constants live here. Modules import from this file instead of
+//! defining their own `pub const` values, ensuring a single source of truth.
+//!
+//! # Sections
+//! - [Analytics](#analytics)
+//! - [Atomic Swaps](#atomic-swaps)
+//! - [Audit & Compliance](#audit--compliance)
+//! - [BFT Consensus](#bft-consensus)
+//! - [Emergency & Circuit Breaker](#emergency--circuit-breaker)
+//! - [Ledger Time](#ledger-time)
+//! - [Liquidity & Fees](#liquidity--fees)
+//! - [Message Passing](#message-passing)
+//! - [Multichain](#multichain)
+//! - [Network Recovery](#network-recovery)
+//! - [Notifications](#notifications)
+//! - [Performance Cache](#performance-cache)
+//! - [Rate Limiting](#rate-limiting)
+//! - [Slashing](#slashing)
+//! - [Sustainability](#sustainability)
+//! - [Upgrade](#upgrade)
+
+// ===== Analytics =====
+
+/// How often bridge metrics may be updated (seconds). Default: 1 hour.
+pub const METRICS_UPDATE_INTERVAL: u64 = 3_600;
+
+// ===== Atomic Swaps =====
+
+/// Minimum timelock duration for an atomic swap (seconds). Default: 1 hour.
+pub const SWAP_MIN_TIMELOCK: u64 = 3_600;
+
+/// Maximum timelock duration for an atomic swap (seconds). Default: 7 days.
+pub const SWAP_MAX_TIMELOCK: u64 = 604_800;
+
+/// Required byte length of a hashlock preimage hash.
+pub const SWAP_HASH_LENGTH: u32 = 32;
+
+// ===== Audit & Compliance =====
+
+/// Maximum number of audit records retained before circular-buffer wrap.
+pub const AUDIT_MAX_RECORDS: u64 = 100_000;
+
+/// Default compliance report period (seconds). Default: 7 days.
+pub const AUDIT_COMPLIANCE_PERIOD: u64 = 604_800;
+
+// ===== BFT Consensus =====
+
+/// Minimum validator stake (stroops, 6-decimal). Default: 100 tokens.
+pub const BFT_MIN_VALIDATOR_STAKE: i128 = 100_000_000;
+
+/// Proposal expiry window (seconds). Default: 24 hours.
+pub const BFT_PROPOSAL_TIMEOUT: u64 = 86_400;
+
+/// Number of consensus rounds per validator rotation epoch.
+pub const BFT_ROTATION_EPOCH_ROUNDS: u64 = 100;
+
+/// Minimum reputation score for a validator to remain active (0-100).
+pub const BFT_MIN_ACTIVE_REPUTATION: u32 = 40;
+
+// ===== Emergency & Circuit Breaker =====
+
+/// Number of seats on the security council.
+pub const EMERGENCY_SECURITY_COUNCIL_SIZE: u32 = 5;
+
+/// Daily volume tracking window (seconds). Default: 24 hours.
+pub const EMERGENCY_DAILY_VOLUME_RESET: u64 = 86_400;
+
+// ===== Ledger Time =====
+
+/// Estimated seconds per Stellar ledger (used for lag calculations).
+pub const LEDGER_EST_SECS: u64 = 5;
+
+// ===== Liquidity & Fees =====
+
+/// Base bridge fee in basis points. Default: 0.10%.
+pub const LIQUIDITY_BASE_FEE_BPS: i128 = 10;
+
+/// Maximum bridge fee in basis points. Default: 5%.
+pub const LIQUIDITY_MAX_FEE_BPS: i128 = 500;
+
+/// Minimum bridge fee in basis points. Default: 0.01%.
+pub const LIQUIDITY_MIN_FEE_BPS: i128 = 1;
+
+/// Pool utilization threshold (basis points) above which dynamic fees apply.
+pub const LIQUIDITY_UTILIZATION_THRESHOLD: u32 = 8_000;
+
+// ===== Message Passing =====
+
+/// Default cross-chain packet timeout (seconds). Default: 24 hours.
+pub const MSG_DEFAULT_PACKET_TIMEOUT: u64 = 86_400;
+
+/// Maximum packet delivery retry attempts.
+pub const MSG_MAX_RETRY_ATTEMPTS: u32 = 5;
+
+/// Base delay between packet retries (seconds). Default: 5 minutes.
+pub const MSG_RETRY_DELAY_BASE: u64 = 300;
+
+// ===== Multichain =====
+
+/// Maximum number of supported external chains.
+pub const MULTICHAIN_MAX_CHAINS: u32 = 100;
+
+/// Maximum number of registered multi-chain assets.
+pub const MULTICHAIN_MAX_ASSETS: u32 = 1_000;
+
+// ===== Network Recovery =====
+
+/// Maximum automatic retry attempts for a failed operation.
+pub const RECOVERY_MAX_RETRY_ATTEMPTS: u32 = 5;
+
+/// Initial exponential-backoff delay (seconds). Default: 1 minute.
+pub const RECOVERY_INITIAL_BACKOFF_SECS: u64 = 60;
+
+/// Maximum backoff delay (seconds). Default: 1 hour.
+pub const RECOVERY_MAX_BACKOFF_SECS: u64 = 3_600;
+
+/// Backoff multiplier applied on each retry.
+pub const RECOVERY_BACKOFF_MULTIPLIER: u64 = 2;
+
+// ===== Notifications =====
+
+/// Sentinel value indicating immediate (non-scheduled) delivery.
+pub const NOTIF_IMMEDIATE_DELIVERY: u64 = 0;
+
+/// Minimum scheduling delay for a notification (seconds). Default: 1 minute.
+pub const NOTIF_MIN_DELAY_SECS: u64 = 60;
+
+/// Maximum scheduling delay for a notification (seconds). Default: 30 days.
+pub const NOTIF_MAX_DELAY_SECS: u64 = 86_400 * 30;
+
+/// Maximum notifications processed per batch.
+pub const NOTIF_BATCH_SIZE: u32 = 100;
+
+/// Default TTL for notification event storage (seconds). Default: 7 days.
+pub const NOTIF_DEFAULT_EVENT_TTL_SECS: u64 = 86_400 * 7;
+
+// ===== Performance Cache =====
+
+/// Bridge summary cache TTL (seconds). Default: 1 hour.
+pub const PERF_CACHE_TTL_SECS: u64 = 3_600;
+
+/// Maximum chains included in the cached top-by-volume list.
+pub const PERF_MAX_TOP_CHAINS: u32 = 20;
+
+// ===== Rate Limiting =====
+
+/// Default maximum calls allowed per rate-limit window.
+pub const RATE_LIMIT_DEFAULT_MAX_CALLS: u32 = 100;
+
+/// Default rate-limit window size in ledgers.
+pub const RATE_LIMIT_DEFAULT_WINDOW_LEDGERS: u32 = 600;
+
+// ===== Slashing =====
+
+/// Slash percentage for double-vote offence (basis points). Default: 50%.
+pub const SLASH_DOUBLE_VOTE_BPS: u32 = 5_000;
+
+/// Slash percentage for invalid-signature offence (basis points). Default: 10%.
+pub const SLASH_INVALID_SIGNATURE_BPS: u32 = 1_000;
+
+/// Slash percentage for inactivity offence (basis points). Default: 5%.
+pub const SLASH_INACTIVITY_BPS: u32 = 500;
+
+/// Slash percentage for byzantine behaviour (basis points). Default: 100%.
+pub const SLASH_BYZANTINE_BPS: u32 = 10_000;
+
+/// Slash percentage for malicious behaviour (basis points). Default: 100%.
+pub const SLASH_MALICIOUS_BPS: u32 = 10_000;
+
+// ===== Sustainability =====
+
+/// Minimum content tokens minted to reach full content-creation score.
+pub const SUSTAIN_CONTENT_SCORE_CAP: u64 = 1_000;
+
+/// Minimum active users to reach full user-adoption score.
+pub const SUSTAIN_USER_SCORE_CAP: u64 = 1_000;
+
+// ===== Upgrade =====
+
+/// Window within which a contract upgrade may be rolled back (seconds).
+/// Default: 30 days.
+pub const UPGRADE_ROLLBACK_WINDOW_SECS: u64 = 86_400 * 30;

contracts/teachlink/src/emergency.rs

@@ -11,11 +11,10 @@ use crate::storage::{CIRCUIT_BREAKERS, CIRCUIT_RESET_SEQ, EMERGENCY_STATE, PAUSE
 use crate::types::{CircuitBreaker, EmergencyState};
 use soroban_sdk::{Address, Bytes, Env, Map, Vec};
 
-/// Authorized pausers (admin + security council)
-pub const SECURITY_COUNCIL_SIZE: u32 = 5;
-
-/// Daily volume reset period (24 hours)
-pub const DAILY_VOLUME_RESET: u64 = 86_400;
+/// Authorized pausers (admin + security council) — re-exported from config.
+pub use crate::config::EMERGENCY_SECURITY_COUNCIL_SIZE as SECURITY_COUNCIL_SIZE;
+/// Daily volume reset period — re-exported from config.
+pub use crate::config::EMERGENCY_DAILY_VOLUME_RESET as DAILY_VOLUME_RESET;
 
 /// Emergency Manager
 pub struct EmergencyManager;

contracts/teachlink/src/ledger_time.rs

@@ -5,11 +5,8 @@
 
 use soroban_sdk::Env;
 
-/// Conservative estimate of seconds per ledger close on Stellar.
-///
-/// Used only to derive a *fallback* ledger-sequence deadline when code is otherwise
-/// timestamp-gated.
-pub const EST_SECS_PER_LEDGER: u64 = 5;
+/// Conservative estimate of seconds per ledger close on Stellar — re-exported from config.
+pub use crate::config::LEDGER_EST_SECS as EST_SECS_PER_LEDGER;
 
 pub fn seconds_to_ledger_delta(seconds: u64) -> u32 {
     // Ceil division to avoid shortening timeouts.

contracts/teachlink/src/lib.rs

@@ -99,6 +99,7 @@ mod audit;
 mod backup;
 mod bft_consensus;
 mod bridge;
+mod config;
 // TODO: Fix collaboration module compilation errors (pre-existing issue)
 // mod collaboration;
 // TODO: Fix content_nft module compilation errors (pre-existing issue)

contracts/teachlink/src/liquidity.rs

@@ -9,17 +9,14 @@ use crate::storage::{FEE_STRUCTURE, LIQUIDITY_POOLS, LP_POSITIONS};
 use crate::types::{BridgeFeeStructure, LPPosition, LiquidityPool};
 use soroban_sdk::{Address, Env, Map, Vec};
 
-/// Base fee in basis points (0.1%)
-pub const BASE_FEE_BPS: i128 = 10;
-
-/// Maximum fee in basis points (5%)
-pub const MAX_FEE_BPS: i128 = 500;
-
-/// Minimum fee in basis points (0.01%)
-pub const MIN_FEE_BPS: i128 = 1;
-
-/// Liquidity utilization threshold for dynamic pricing (80%)
-pub const UTILIZATION_THRESHOLD: u32 = 8000;
+/// Base fee in basis points — re-exported from config.
+pub use crate::config::LIQUIDITY_BASE_FEE_BPS as BASE_FEE_BPS;
+/// Maximum fee in basis points — re-exported from config.
+pub use crate::config::LIQUIDITY_MAX_FEE_BPS as MAX_FEE_BPS;
+/// Minimum fee in basis points — re-exported from config.
+pub use crate::config::LIQUIDITY_MIN_FEE_BPS as MIN_FEE_BPS;
+/// Utilization threshold for dynamic pricing — re-exported from config.
+pub use crate::config::LIQUIDITY_UTILIZATION_THRESHOLD as UTILIZATION_THRESHOLD;
 
 /// Congestion multiplier steps
 pub const CONGESTION_STEP_1: u32 = 5000; // 50% utilization

contracts/teachlink/src/message_passing.rs

@@ -12,14 +12,12 @@ use crate::types::{CrossChainPacket, MessageReceipt, PacketStatus};
 use crate::validation::NumberValidator;
 use soroban_sdk::{Bytes, Env, Map, Vec};
 
-/// Default packet timeout (24 hours)
-pub const DEFAULT_PACKET_TIMEOUT: u64 = 86_400;
-
-/// Maximum retry attempts
-pub const MAX_RETRY_ATTEMPTS: u32 = 5;
-
-/// Retry delay in seconds (exponential backoff)
-pub const RETRY_DELAY_BASE: u64 = 300; // 5 minutes
+/// Default packet timeout — re-exported from config.
+pub use crate::config::MSG_DEFAULT_PACKET_TIMEOUT as DEFAULT_PACKET_TIMEOUT;
+/// Maximum retry attempts — re-exported from config.
+pub use crate::config::MSG_MAX_RETRY_ATTEMPTS as MAX_RETRY_ATTEMPTS;
+/// Retry delay base — re-exported from config.
+pub use crate::config::MSG_RETRY_DELAY_BASE as RETRY_DELAY_BASE;
 
 /// Message Passing Manager
 pub struct MessagePassing;