C14: Legacy deletion + ADR-0005 + zero-warnings CI guard

[filipeforattini]

Parent

#46

What to build

The closing slice. With every in-tree caller migrated to the new path (C2, C4, C11, C12), delete the legacy detection modules and enums; record ADR-0005; add a CI guard preventing regression into the deprecated state.

Deletions:

• src/discovery/tech_fingerprint.rs (1312 LOC)
• src/runner/challenge.rs (218 LOC)
• src/antibot/block_detector.rs (640 LOC)
• src/runner/fetcher/auto.rs (per ADR-0004)
• src/antibot/mod.rs::detect_from_html / detect_from_http_response / detect_from_cookies (≈290 LOC of detection-only code; bypass/cookie_pin/solver/telemetry/recaptcha submodules stay — action paths, ADR-0003)
• src/antibot/signatures.rs data tables redistributed into the sources that consume them
• src/error.rs::AntibotVendor enum
• src/antibot/mod.rs::ChallengeVendor enum
• From<AntibotVendor> for Vendor and From<ChallengeVendor> for Vendor (no callers remain)

Adds:

• docs/adr/0005-cutover-and-legacy-deletion.md records the cutover decision and the irreversible deletions
• CONTEXT.md updated to drop the ChallengeDetector "Avoid" disclaimer and the Vendor ambiguity entry (resolved)
• CI step in .github/workflows/*.yml (or equivalent) running cargo build --all-features --tests 2>&1 | grep -c "deprecated" and asserting zero deprecation warnings from crawlex code

After this slice, cargo build --all-features --tests produces zero deprecation warnings and the legacy detection modules are gone from the tree.

Acceptance criteria

• src/discovery/tech_fingerprint.rs deleted
• src/runner/challenge.rs deleted
• src/antibot/block_detector.rs deleted
• src/runner/fetcher/auto.rs deleted
• antibot::detect_from_html / detect_from_http_response / detect_from_cookies deleted
• error::AntibotVendor enum deleted
• antibot::ChallengeVendor enum deleted
• antibot::signatures data tables redistributed (file deleted)
• src/lib.rs updated — no more pub mod tech_fingerprint, pub mod challenge, etc.
• docs/adr/0005-cutover-and-legacy-deletion.md written
• CONTEXT.md updated to reflect the post-deletion state
• CI guard added that fails build on any deprecation warning from crawlex code
• cargo build --all-features --tests: zero deprecation warnings
• cargo test --all-features --no-fail-fast: same pre-existing failure count as main
• cargo test --all-features --test runner_ndjson_regression: byte-stable
• PR description summarizes total LOC deletion across all modules (~2400 LOC)

Blocked by

• forattini-dev/crawlex#
• C4: process_job HttpSpoof+Auto cutover to runner.run #56
• C11: Test suite migration to fingerprint::Vendor #55
• C12: CLI subcommand crawlex fingerprint <url> #58