revert: remove codebase intelligence system

Rolled back the intel system due to overengineering concerns:
- 1200+ line hook with SQLite graph database
- 21MB sql.js dependency
- Entity generation spawning additional Claude calls
- Complex system with unclear value

Removed:
- /gsd:analyze-codebase command
- /gsd:query-intel command
- gsd-intel-index.js, gsd-intel-session.js, gsd-intel-prune.js hooks
- gsd-entity-generator, gsd-indexer agents
- entity.md template
- sql.js dependency

Preserved:
- Model profiles feature
- Statusline hook
- All other v1.9.x improvements

-3,065 lines removed

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

agents/gsd-planner.md

@@ -416,9 +416,6 @@ Output: [What artifacts will be created]
 @.planning/ROADMAP.md
 @.planning/STATE.md
 
-# Codebase intelligence (if exists)
-@.planning/intel/summary.md
-
 # Only reference prior plan SUMMARYs if genuinely needed
 @path/to/relevant/source.ts
 </context>
@@ -1039,25 +1036,6 @@ If exists, load relevant documents based on phase type:
 | (default) | STACK.md, ARCHITECTURE.md |
 </step>
 
-<step name="load_codebase_intelligence">
-Check for codebase intelligence:
-
-```bash
-cat .planning/intel/summary.md 2>/dev/null
-```
-
-If exists, this provides:
-- File count and structure overview
-- Detected naming conventions (use these when creating new files)
-- Key directories and their purposes
-- Export patterns
-
-**How to use:**
-- Follow detected naming conventions when planning new exports
-- Place new files in directories that match their purpose
-- Reference existing patterns when describing implementation
-</step>
-
 <step name="identify_phase">
 Check roadmap and existing phases: