docs(outline): add AI agent context set (Outline layer)

Add docs/outline/00-index.md plus system overview, config/env, code map,
and agent runbook in Simplified Technical English. Link the set from the
README. Completes the project-docs Outline layer.

docs/outline/03-code-map.md

@@ -0,0 +1,69 @@
+# obsidian-sorter — Code Structure Map
+
+> **Target**: AI Agents — ASD-STE100 Simplified Technical English.
+
+## Dependencies
+
+The sorter uses the Python standard library only. It requires Python 3.10 or
+later. It uses no PyYAML, no HTTP library, and no JEV SDK. Deploy with `rsync`.
+Hosts need no pip.
+
+## Layout
+
+| Path | Purpose |
+| :--- | :--- |
+| `sorter/__main__.py` | Module entry point. Calls `cli.main`. |
+| `sorter/cli.py` | Argument parser and all commands. |
+| `sorter/models.py` | Data types. Folder-to-type map. `Note`, `Proposal`. |
+| `sorter/vault.py` | Vault scanning and index introspection. |
+| `sorter/frontmatter.py` | Minimal YAML frontmatter reader and writer. |
+| `sorter/classify.py` | Tier 1 deterministic classifier. |
+| `sorter/jev.py` | TypeSafe JEV client. Cost tracking. |
+| `sorter/tier2.py` | Tier 2 semantic classifier. Hybrid logic. |
+| `sorter/writer.py` | Plans, frontmatter merge, TOC insert, apply. |
+| `sorter/watch.py` | Inbox watcher. Maintains proposals. |
+| `tests/run_tests.py` | Test suite. Runs against an isolated vault copy. |
+| `tools/normalize_tags.py` | One-off tag cleanup tool. |
+| `docs/` | Diagrams, handoff notes, and this Outline set. |
+
+## Entry Points
+
+1. **Command wrapper**: `~/bin/obsidian-sort`. It changes to `~/obsidian-sorter`,
+   then runs `python3 -m sorter` with the vault and inbox set.
+2. **Module**: `python3 -m sorter --vault <path> --inbox <name> <command>`.
+3. **Systemd unit**: `ExecStart=~/bin/obsidian-sort watch --interval 10`.
+
+## Commands
+
+Read-only commands:
+
+| Command | Purpose |
+| :--- | :--- |
+| `scan` | Report vault shape. |
+| `propose <file>` | Classify one note. |
+| `inbox` | Classify every inbox note. |
+| `validate` | Replay the classifier against known-good notes. |
+| `benchmark` | Measure accuracy and cost of the hybrid classifier. |
+
+Write commands:
+
+| Command | Purpose |
+| :--- | :--- |
+| `sort <file>` | Plan, then optionally apply, sorting for one note. |
+| `sort-inbox` | Plan, then optionally apply, sorting for the whole inbox. |
+| `watch` | Watch the inbox and maintain proposals. |
+
+## Core Data Flow
+
+`vault.py` scans notes into `Note` objects. `classify.py` picks a folder with
+rules. `tier2.py` escalates to `jev.py` when needed. `writer.py` builds a
+`Proposal` and a `Plan`, then applies it. `watch.py` connects the classifier to
+the file system on a 10-second poll.
+
+## Where to Fix Things
+
+- **Misfiled notes**: edit `FOLDER_NOTES` in `sorter/tier2.py`. This teaches the
+  model the meaning of each folder.
+- **Rule behaviour**: edit `sorter/classify.py`.
+- **Type or folder rules**: edit `sorter/models.py`.
+- **Filing safety**: edit `sorter/writer.py`.