Merge remote-tracking branch 'origin/master' into feat/plan-mode

Master arrivals re-grafted onto the plan-mode surfaces:
- Package invariant runtime contracts: every package owns ./invariant —
  added the dsh-mode companion (mode/set payload validation: non-empty
  trimmed name), its unit spec, exports/peer wiring, and the mode group in
  the tsconfig invariant paths glob.
- Interception waterfalls gained an AbortSignal parameter
  (agent/prompt-submit, agent/turn-continuation) and ToolExecutionInput.signal
  became required: listeners and test dispatch updated; the exit tool now
  forwards exec.signal unconditionally.
- TUI question dialog: master's position/unanswered header layout kept,
  the plan-review detail block re-grafted between question and answers.
- LSP capability family arrived: lsp tool joins the catalog pin, dsh-lsp
  examples deps beside dsh-mode; lsp-definition snapshot refreshed with
  the mode command and modes advertisement.
- docs/architecture.md and packages/README.md regenerated tables re-grafted
  (ctx.modes row, mode package row) and condensed within word ceilings.
- examples/acp-agent cordis.yml: kept the deployment-owned plan instructions
  (incl. the conversational-agreement sentence) beside master's routed-model
  compaction comment; snapshot expected outputs refreshed keyless and noise
  fixtures restored.

examples/tui-agent/README.md

@@ -10,7 +10,7 @@ pnpm run demo:tui
 
 The command needs `DEEPSEEK_API_KEY` in the environment or gitignored repository-root `.env`. Set `RESUME_SESSION_ID` to reopen a persisted conversation under `./.sessions`.
 
-The TUI renders Markdown history, reasoning, tool-owned terminal/diff/generic cards, token totals, and the latest todo list. Enter submits or steers while the agent runs; Ctrl+O expands cards, Ctrl+R toggles reasoning, Escape cancels, and `/help` lists commands. `ask_user_question` opens a keyboard-driven overlay.
+The TUI renders Markdown history, reasoning, tool-owned terminal/diff/generic cards, token totals, and the latest todo list. Long tool bodies keep a head/tail preview; Ctrl+O expands or collapses every card. Enter submits or steers while the agent runs, Ctrl+R toggles reasoning, Escape cancels, and `/help` lists commands. `/model` opens a keyboard selector for the current provider catalog; use Up/Down and Enter, or `/model <model>` and `/model <provider>/<model>` for direct selection. `ask_user_question` opens a wide bottom-left keyboard panel with batch progress and numbered options.
 
 Run `pnpm run demo:code-mode tui` for the Code Mode overlay.