Make KB Capture project-centric

- Sessions now live inside project folders: <Project>/_capture/<session>/
- Project picker dropdown (scans projects folder)
- Auto-discovers projects with KB/ folder or _context.md
- Windows: D:/ATODrive/Projects
- Linux: ~/obsidian-vault/2-Projects

This aligns with the KB structure where Mario updates:
- KB/dev/gen-XXX.md (session captures)
- Images/screenshot-sessions/ (frames)

docs/KB-CAPTURE.md

@@ -21,12 +21,14 @@ uv run kb-capture
 ## Workflow
 
 ### 1. Start Session
-- Open KB Capture (system tray or GUI)
-- Enter project name (e.g., "P04-GigaBIT-M1")
+- Open KB Capture (GUI)
+- **Select project** from dropdown (scans your projects folder)
 - Enter session description (e.g., "Vertical support refinement")
 - Select type: **Design** (CAD) or **Analysis** (FEA)
 - Click **Start Session**
 
+> Projects are auto-discovered from your projects folder (D:/ATODrive/Projects on Windows)
+
 ### 2. Record Clips
 While working in NX/CAD:
 - Press **Ctrl+Shift+R** to start recording
@@ -63,24 +65,34 @@ After each clip:
 
 ## Output
 
-After ending a session:
+Sessions are stored **inside the project folder**:
 
 ```
-sessions/<session-id>/
-├── clips/
-│   ├── clip-001.mp4
-│   ├── clip-002.mp4
-│   └── ...
-├── session.json
-└── clawdbot_export/
-    ├── merged.mp4         # All clips merged
-    ├── transcript.json    # Whisper transcription
-    ├── frames/            # Extracted at "screenshot" triggers
-    │   ├── 01_00-30.png
-    │   └── ...
-    └── metadata.json      # Session info for Clawdbot
+/2-Projects/<ProjectName>/
+├── KB/
+│   └── dev/                      # Mario creates gen-XXX.md here
+├── Images/
+│   └── screenshot-sessions/      # Mario moves frames here
+└── _capture/                     # Session staging area
+    └── <session-id>/
+        ├── clips/
+        │   ├── clip-001.mp4
+        │   └── ...
+        ├── session.json
+        └── clawdbot_export/      # Ready for Mario
+            ├── merged.mp4
+            ├── transcript.json
+            ├── frames/
+            │   ├── 01_00-30.png
+            │   └── ...
+            └── metadata.json
 ```
 
+**Key insight:** Sessions belong to PROJECTS, not to KB Capture. This means:
+- All project data stays together
+- Mario knows which KB to update
+- Easy to archive/delete projects
+
 ## What Happens Next
 
 1. **Syncthing** syncs `clawdbot_export/` to Clawdbot