feat: make beta forward channel and remove MCP surface

[hefxpzwk]

Scope

• Move forward release policy from preview/stable to beta/stable for 0.1.1-beta.0.
• Remove MCP-facing CLI/runtime/product/docs surfaces.
• Keep TFY agent routing centered on supported Codex/Claude Code official hooks plus wrapper/adapter routes.
• Preserve old local evidence readability through Unknown runtime enum deserialization instead of reintroducing removed route names.
• Update npm package metadata, release helpers, CI labels, site/README/docs, and tests.

Validation

• ./scripts/verify.sh
• cargo test -p tfy-cli --test product_ux gain_reads_default_agent_ledger -- --nocapture
• cargo test -p tfy-runtime --test runtime_contract -- --nocapture
• rg -n "\\bmcp\\b|MCP|Mcp|mcp_stdio|tfy mcp|mcp_" . --glob '!target/**' --glob '!node_modules/**' --glob '!dist/**' --glob '!coverage/**' returned no output
• Stale public wording grep for old preview install/deleted tool names returned no output
• Independent code-reviewer: APPROVE
• Independent architect: CLEAR

Supported claims

• Beta is the forward development/validation channel; stable remains the latest channel only for completed stable releases.
• tfy start --agent prepares Codex and Claude Code project routes plus the wrapper foundation.
• Setup/config remains evidence-gated; real route support still requires raw/ledger/no-negative/positive-savings evidence.

Risk notes

• Broad change because release policy, docs, CLI product surface, runtime enums, and tests move together.
• Actual GitHub Actions release dispatch and npm Trusted Publishing were not executed in this PR.
• Historical preview references remain only where they describe historical exact versions or compatibility behavior, not forward release policy.