docs(router): Phase 282 P2 - Comment archaeology + TODO cleanup

Step 2: Router comment updates
- Update Phase references (183, 273, 282 retained)
- Document ExtractionBased status (Pattern8/9 already done)
- Remove obsolete Phase references (187, 193, 195)

Step 3: TODO cleanup
- pattern5: Remove completed TODO (lowering fully implemented)
- pattern_pipeline: Clarify loop_update_summary status (reserved)
- apply_policy: Mark current_static_box_name as low-priority refactor

Step 4: Pattern3 legacy references
- Simplify module docstring (remove legacy mode details)
- Update inline comments (legacy removal Phase 242-EX-A)

Changes: Comment/docstring only (zero behavior change)
Test: cargo build --release (0 errors)

src/mir/builder/control_flow/joinir/patterns/router.rs

@@ -1,7 +1,6 @@
 //! Pattern Router - Table-driven dispatch for loop patterns
 //!
 //! Phase 194: Replace if/else chain with table-driven routing
-//! Phase 193: Modularized feature extraction using ast_feature_extractor module
 //!
 //! # Architecture
 //!
@@ -30,8 +29,7 @@ use crate::mir::builder::control_flow::plan::lowerer::PlanLowerer;
 use crate::mir::builder::control_flow::plan::normalizer::PlanNormalizer;
 use crate::mir::builder::control_flow::plan::verifier::PlanVerifier;
 
-/// Phase 193: Import AST Feature Extractor Box
-/// (declared in mod.rs as pub module, import from parent)
+/// AST Feature Extractor (declared in mod.rs as pub module, import from parent)
 use super::ast_feature_extractor as ast_features;
 
 /// Phase 92 P0-2: Import LoopSkeleton for Option A
@@ -81,24 +79,21 @@ pub(crate) struct LoopPatternContext<'a> {
 impl<'a> LoopPatternContext<'a> {
     /// Create new context from routing parameters
     ///
-    /// Phase 194+: Automatically detects continue/break statements in body
-    /// Phase 192: Extract features and classify pattern from AST
-    /// Phase 193: Feature extraction delegated to ast_feature_extractor module
-    /// Phase 131-11: Detects infinite loop condition
-    /// Phase 137-6-S1: Use choose_pattern_kind() SSOT entry point
-    /// Phase 92 P0-2: Added skeleton parameter (None for backward compatibility)
+    /// Automatically detects continue/break statements in body
+    /// Extracts features and classifies pattern from AST
+    /// Detects infinite loop condition
+    /// Uses choose_pattern_kind() SSOT entry point
     pub(crate) fn new(
         condition: &'a ASTNode,
         body: &'a [ASTNode],
         func_name: &'a str,
         debug: bool,
     ) -> Self {
-        // Phase 193: Use AST Feature Extractor Box for break/continue detection
+        // Use AST Feature Extractor for break/continue detection
         let has_continue = ast_features::detect_continue_in_body(body);
         let has_break = ast_features::detect_break_in_body(body);
 
-        // Phase 193: Extract features using modularized extractor
-        // Phase 131-11: Pass condition for infinite loop detection
+        // Extract features (includes infinite loop detection)
         let features = ast_features::extract_features(condition, body, has_continue, has_break);
 
         // Phase 137-6-S1: Use SSOT pattern selection entry point
@@ -140,9 +135,6 @@ impl<'a> LoopPatternContext<'a> {
     }
 }
 
-/// Phase 193: Feature extraction moved to ast_feature_extractor module
-/// See: src/mir/builder/control_flow/joinir/patterns/ast_feature_extractor.rs
-
 /// Phase 272 P0.2 Refactoring: can_lower() strategy classification
 ///
 /// Clarifies the two main detection strategies used across patterns:
@@ -198,9 +190,12 @@ pub(crate) struct LoopPatternEntry {
 /// Array order defines priority - earlier entries are tried first.
 /// Pattern5 (most specific) → Pattern4 → Pattern3 → Pattern1 → Pattern2
 ///
-/// # Current Patterns (Phase 131-11: Pattern 5 added)
+/// # Current Patterns (Structure-based detection, established Phase 131-11+)
 ///
-/// All patterns now use structure-based detection via LoopFeatures and classify():
+/// Pattern detection strategies (updated Phase 282 P0):
+/// - Pattern6/7: ExtractionBased (Plan line, Phase 273+)
+/// - Pattern8/9: ExtractionBased (extraction functions, already implemented)
+/// - Pattern1-5: StructureBased (LoopFeatures classification, legacy)
 ///
 /// - Pattern 5: Infinite Loop with Early Exit (llvm_stage3_loop_only.hako) [Phase 131-11]
 ///   - Detection: pattern_kind == InfiniteEarlyExit
@@ -271,14 +266,14 @@ pub(crate) static LOOP_PATTERNS: &[LoopPatternEntry] = &[
 /// Returns Ok(None) if no pattern matched.
 /// Returns Err if a pattern matched but lowering failed.
 ///
-/// # Phase 183: Structure-based routing
+/// # Router Architecture (Structure-based routing established Phase 183)
 ///
-/// This router uses the centralized pattern classification system:
-/// - Pattern detection: `ctx.pattern_kind` (from `loop_pattern_detection::classify`)
-/// - No redundant pattern detection in detect functions
-/// - All patterns use structure-based classification
+/// This router uses multiple detection strategies:
+/// - Plan-based (Pattern6/7): extract_*_plan() → DomainPlan (Phase 273+ SSOT)
+/// - Extraction-based (Pattern8/9): extract_*() functions (already implemented)
+/// - Structure-based (Pattern1-5): ctx.pattern_kind classification (legacy)
 ///
-/// # Phase 273 P3: Plan Line is Current SSOT for Pattern6/7
+/// # Plan Line SSOT for Pattern6/7 (Phase 273+)
 ///
 /// This function implements the following routing strategy:
 /// 1. Try Plan-based Pattern6 (extract_scan_with_init_plan) → DomainPlan
@@ -375,7 +370,6 @@ pub(crate) fn route_loop_pattern(
     // Phase 273 P0.1: Pattern6 skip logic removed (entry no longer in LOOP_PATTERNS)
     for entry in LOOP_PATTERNS {
         if (entry.detect)(builder, ctx) {
-            // Phase 195: Use unified trace for pattern matching
             let log_msg = format!("route=joinir pattern={} (Phase 194+)", entry.name);
             trace::trace().pattern("route", &log_msg, true);
             return (entry.lower)(builder, ctx);
@@ -383,7 +377,6 @@ pub(crate) fn route_loop_pattern(
     }
 
     // No pattern matched - return None (caller will handle error)
-    // Phase 187-2: Legacy LoopBuilder removed, all loops must use JoinIR
     if ctx.debug {
         trace::trace().debug(
             "route",