feat(#2160): collapse verbose '(1M context)' model suffix to compact (1M) badge (#2173)

* feat(#2160): collapse verbose '(1M context)' model suffix to compact (1M) badge

Claude Code appends " (1M context)" to the model display name in
long-context sessions, eating 12 characters of statusline width. Collapse
it to " (1M)" — the signal stays, the width doesn't. Any other display
name passes through unchanged.

Claude-Session: https://claude.ai/code/session_01Hme55Pvq6BhpgwBcyC5HAg

* docs(#2160): changeset fragment for PR #2173

* fix(#2160): review fixes — ctx variant, boundary test, changeset format

- broaden the suffix match with a context|ctx alternation (approval-condition
  variant the regex missed)
- pin non-context parentheticals ((beta), (deprecated)) as untouched
- changeset body ends with the (#2160) citation per house convention

Claude-Session: https://claude.ai/code/session_01Hme55Pvq6BhpgwBcyC5HAg

* test: regenerate golden-install-parity fixtures for the statusline hook change

Claude-Session: https://claude.ai/code/session_01Hme55Pvq6BhpgwBcyC5HAg

---------

Co-authored-by: Tom Boucher <trekkie@nomorestars.com>

docs/ARCHITECTURE.md

@@ -286,7 +286,7 @@ Runtime hooks that integrate with the host AI agent:
 
 | Hook | Event | Purpose |
 |------|-------|---------|
-| `gsd-statusline.js` | `statusLine` | Displays model, task, directory, and context usage bar |
+| `gsd-statusline.js` | `statusLine` | Displays model (long-context suffixes like `(1M context)` collapse to a compact `(1M)` badge), task, directory, and context usage bar |
 | `gsd-context-monitor.js` | `PostToolUse` / `AfterTool` | Injects agent-facing context warnings at 35%/25% remaining |
 | `gsd-check-update.js` | `SessionStart` | Foreground trigger for the background update check |
 | `gsd-ensure-canonical-path.js` | `SessionStart` | For Claude Code plugin installs, symlinks `~/.claude/gsd-core/{bin,contexts,references,templates,workflows}` to the plugin's bundled tree so `@~/.claude/gsd-core/...` includes resolve; runs first in `SessionStart`, no-op in classic installs, self-heals after `claude plugin update` (#997) |