feat(tools): run_code description param + native-parity dispatch logging + web code-mode seam

run_code gains a required bash-style description parameter: presentCall
titles the card with it and moves the program to rawInput, so every
surface gets a readable label. tool/code-dispatch now logs each
sub-call's complete content/isError (the tool/result vocabulary),
replacing the bounded resultSummary and deleting the summarize/cwd
machinery — a UI renders sub-calls through the identical path as native
results. The dsh config tree mounts the worker code runtime and reads
DSH_TOOLS_MODE (temporary seam until per-session mode selection lands).

Session format stays v0 (pre-release churn). Code-mode ACP/TUI fixtures
re-recorded; TUI presenter pin refreshed; catalogs regenerated. Keyless
web smoke pins the code-mode wire contract (tools=[run_code] + SDK
prompt section).

examples/headless-agent/tests/code-mode.e2e.ts

@@ -85,7 +85,7 @@ function runCode(harness: Context, code: string, signal: AbortSignal = testToolS
   return harness.tools.execute({
     callId: CallId(`keyless-code-${++keylessCall}`),
     name: RUN_CODE_NAME,
-    arguments: { code },
+    arguments: { code, description: 'Run the e2e program' },
     signal,
   })
 }