Feat/fix discord untrusted boundary

[ArnabChatterjee20k]

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Greptile Summary

This PR prevents generated Discord answer bodies from being reintroduced into intent-classification transcripts, replacing them with a persisted routing-intent marker.

• Adds stable routing labels and propagates them through issue metadata.
• Persists routing intent on answered attempts through a new SQLite migration.
• Uses structural markers for classification transcripts while retaining full answer grounding in trusted transcripts.
• Adds coverage for fixed-label and legacy fallback behavior.

Confidence Score: 5/5

The PR appears safe to merge with no concrete actionable failures identified.

The persisted label is derived from a fixed intent enum, legacy rows have a safe generic fallback, and classification transcripts no longer reintroduce generated answer text while trusted grounding retains the full answer.

Important Files Changed

Filename	Overview
crates/claudear-engine/src/intent.rs	Adds fixed routing labels for each intent variant; no actionable defect identified.
crates/claudear-engine/src/processing.rs	Separates full reply grounding from classification-safe structural markers and persists answer intent in both answer paths.
crates/claudear-engine/src/watcher.rs	Stamps the upstream classified intent onto issues before background processing.
crates/claudear-storage/src/lib.rs	Extends the tracker contract with optional intent persistence and retrieval while preserving default implementations.
crates/claudear-storage/src/migrator.rs	Registers migration version 11 and updates migration tests to verify the new column.
crates/claudear-storage/src/sqlite.rs	Persists and retrieves routing intent while preserving an existing value when callers omit it.
migrations/V11__fix_attempt_routing_intent.sql	Adds the nullable routing_intent column needed for backward-compatible structural markers.

_{Reviews (1): Last reviewed commit: "fix(engine): stop re-injecting answer bo..." | Re-trigger Greptile}