feat(deepseek): add DeepSeek Harness (dsh) as a ninth CLI run mode

Adds `mode: 'deepseek'` alongside claude/shell/opencode/codex/gemini/
antigravity/pi/grok, plus a shortcut that opens the harness's own browser UI
as a Codeman web tab.

DeepSeek is wired unlike its siblings in three ways, each of which is the
reason for a design decision rather than an accident:

1. The agent is a PROFILE, not the binary. `dsh` is a launcher over
   $DSH_HOME/profiles/<name>, and DeepSeek ships only `web`, `headless` and
   `base` -- the interactive terminal front door is always a third-party
   plugin. So availability is two questions: `isDeepSeekAvailable()` (binary)
   and `isDeepSeekRunnable()` (binary AND a pane-capable profile). The Run
   button gates on the latter, because reporting only the binary would spawn a
   pane that dies on arrival. When the binary is present but no profile is,
   the run menu offers to install one (POST /api/deepseek/install-profile).

2. The permission switch is an env var, not a flag. The harness has no
   command-line permission option; its sandbox/approval rows read
   DSH_PERMISSION_MODE (read-only / workspace-write / danger-full-access).
   Exported via `tmux setenv`, never on the spawn line. Absent = the harness's
   own workspace-write, which still asks, so the multi-user clamp is the
   only-if-sent branch and clamps to workspace-write, never read-only.

3. It is the only non-claude mode that passes hooksAvailableForMode(), and it
   earned that. The terminal front door reports idle/working/blocked to a
   supervising process over a generic env-gated contract; a generated shim
   (deepseek-status-shim.ts) makes Codeman that supervisor and forwards each
   report to /api/hook-event as stop / agent_working / permission_prompt. So a
   dsh session gets definitive respawn triggers, real wait-endpoint signals and
   real Approvals Inbox items instead of output-stabilization guesswork.
   `agent_working` is new (157th SSE constant) and joins
   APPROVAL_RESOLVING_EVENTS so a dialog answered in the terminal clears its
   alert at once.

The resolver needs the strictest identity probe of the family: `dsh` is not
merely a squattable npm name, Debian ships an unrelated `dsh` (dancer's shell),
so `dsh --help` must print the harness's own banner before a candidate is
handed a spawn line.

Model is deliberately not a session field -- it is a composition entry in the
profile's config tree. Env allowlist gains DSH_* and DEEPSEEK_* only; provider
keys named by a settings-file `apiKeyEnv` stay out, which is pi's
34-provider-key problem in a new shape.

Verified live against dsh 0.1.1-rc.2 and @deepseek-harness-tui/dsh-tui: the
status endpoint's two-part answer, the no-profile refusal, the profile
bootstrap, a real session whose pane runs `dsh --profile dsh-tui` with the
permission mode injected via setenv, and the full status bridge -- a
send-and-wait returned signal "stop" from a real turn, and blocked/working
created and cleared an Approvals Inbox item.

Docs: docs/deepseek-integration.md (guide), docs/deepseek-integration-plan.md
(decisions + honest gaps). Tests: test/deepseek-mode.test.ts,
test/deepseek-cli-resolver.test.ts.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

skills/codeman/reference/verbs.md

@@ -343,7 +343,7 @@ recovered by submitting it with `{"input":"\r"}`.
 
 ⚠️ `stop` and `blocked` fire for `claude` sessions only (they are Claude Code hooks,
 and only when the workspace actually has them, see [§5.1](#51-where-to-spawn)). On
-`shell`/`opencode`/`codex`/`gemini`/`antigravity`/`pi`/`grok`, requesting them explicitly is a
+`shell`/`opencode`/`codex`/`gemini`/`antigravity`/`pi`/`grok`/`deepseek`, requesting them explicitly is a
 400, and lifecycle transitions there are coarse (a short shell command may emit **no**
 `idle` transition at all, verified live), so synchronize those with markers.
 
@@ -369,7 +369,7 @@ from the transcript file, which is flushed slightly *after* the `stop` hook fire
 single read taken the instant send-and-wait returns comes back `""` even though the
 turn finished (verified live: empty on the first call, full text seconds later). `text`
 is also `""` before the worker's first completed turn, and always `""` for modes with
-no transcript (`shell`, `opencode`, `gemini`, `antigravity`, `pi`, `grok`; the first four
+no transcript (`shell`, `opencode`, `gemini`, `antigravity`, `pi`, `grok`, `deepseek`; the first four
 verified live, pi from the same source path), which is
 why the loop above is bounded rather than open-ended. Fall back to the terminal buffer
 there, tail in **bytes** (`textOutput` in `GET .../output` stays empty for interactive
@@ -454,7 +454,7 @@ turn), and both better than diffing terminal samples:
 ```
 
 ⚠️ `active-tools` is parsed out of Claude's own output format, so it is **empty for
-`opencode`/`codex`/`gemini`/`antigravity`/`pi`/`grok`** (those parsers are skipped wholesale) and
+`opencode`/`codex`/`gemini`/`antigravity`/`pi`/`grok`/`deepseek`** (those parsers are skipped wholesale) and
 in practice empty for `shell`. Source-verified, not measured live.
 
 Only if neither helps: sample `terminal?tail=` twice a few seconds apart. A changing