feat(joinir): phase 100 P1 - pinned local analyzer and wiring into CapturedEnv

- Implement PinnedLocalAnalyzer box to identify pinned loop-outer locals
  * Pure AST analysis (no MIR dependencies)
  * Detects locals: defined before loop, referenced in loop, NOT assigned in loop
  * 5 unit tests covering all edge cases (no assignment, assigned, empty body, etc.)
- Integrate PinnedLocalAnalyzer into pattern2_with_break.rs
  * Call analyzer with loop body AST and candidate locals from variable_map
  * Wire pinned locals into CapturedEnv with CapturedKind::Pinned
  * Fail-Fast on host_id lookup failure or analyzer errors
- Update loop_body_local_init.rs resolver to search CapturedEnv
  * New search order: LoopBodyLocalEnv → ConditionEnv → CapturedEnv
  * Access via cond_env.captured (already integrated in ConditionEnv)
  * Updated error message to show full search order
- All existing tests pass (1101 passed, 1 unrelated failure)
- Smoke tests verified: phase96_json_loader_next_non_ws_vm, phase94_p5b_escape_e2e

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

src/mir/loop_pattern_detection/mod.rs

@@ -743,4 +743,7 @@ pub use trim_detector::{TrimDetectionResult, TrimDetector};
 
 // Phase 79: BindingMapProvider trait (centralize feature gate)
 pub mod binding_map_provider;
+
+// Phase 100 P1-2: Pinned Local Analyzer
+pub mod pinned_local_analyzer;
 pub use binding_map_provider::BindingMapProvider;