refactor(acp): trim unreachable bridge surface (branding knobs, kind-sniffing fallback)

Two pieces of dsh-acp surface were unreachable from any shipped config:

- AcpConfig.agentName/agentVersion: the app package hands the bridge only
  { model, systemPrompt }, so no leaf cordis.yml could set them; they were
  settable only by direct-mounting the bridge (a unit test). Hardcode
  agentInfo at the initialize site and delete the fields, their schema
  defaults, the ?? fallbacks, and the TODO(double-default) whose subject
  vanishes. The handshake wire value is unchanged (all snapshot initialize
  lines byte-identical).

- The toolKindFor name heuristic special-cased bash*/read*/write/edit*
  names in the generic-fallback path, violating the bridge's own design
  rule ("the bridge never special-cases tool names"). Every first-party
  tool ships its kind via presentCall; the fallback now renders the
  neutral kind 'other'. The fallback is reachable when a presentCall
  throws OR when model args fail the tool schema (defineTool's presentCall
  wrapper returns undefined on violations) — the latter shows up in one
  committed golden (hook-codex-posttool-block: three bash calls missing
  the required description), whose kind cells flip execute->other. That
  3-line golden refresh is the whole transcript delta.

The empty-arguments branch of parseToolArguments lost its only exercise
with the deleted heuristic test; it is live behavior (JSON.parse('')
throws, so the guard is what renders a zero-arg call as rawInput {}), so
it gets a dedicated pin instead of deletion.

RFC moved to docs/rfc/implemented/simplification/ and amended to shipped
reality: fallback reachability includes schema-invalid args, and the
golden churn is exactly the three kind cells (the original zero-churn
claim held only for the branding half).

examples/acp-agent/tests/snapshots/hook-codex-posttool-block/stdout.golden.jsonl

@@ -79,7 +79,7 @@
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_thought_chunk","content":{"type":"text","text":" or"}}}}
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_thought_chunk","content":{"type":"text","text":" command"}}}}
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_thought_chunk","content":{"type":"text","text":"."}}}}
-{"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"tool_call","toolCallId":"call_00_XLxXjqVljRIC2KwFZCKX3369","title":"bash","kind":"execute","status":"in_progress","rawInput":{"command":"echo HELLO"}}}}
+{"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"tool_call","toolCallId":"call_00_XLxXjqVljRIC2KwFZCKX3369","title":"bash","kind":"other","status":"in_progress","rawInput":{"command":"echo HELLO"}}}}
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"tool_call_update","toolCallId":"call_00_XLxXjqVljRIC2KwFZCKX3369","status":"failed","content":[{"type":"content","content":{"type":"text","text":"tool output rejected by codex policy: summarize instead"}}]}}}
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_thought_chunk","content":{"type":"text","text":"The"}}}}
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_thought_chunk","content":{"type":"text","text":" tool"}}}}
@@ -99,7 +99,7 @@
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_thought_chunk","content":{"type":"text","text":" invoke"}}}}
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_thought_chunk","content":{"type":"text","text":" it"}}}}
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_thought_chunk","content":{"type":"text","text":"."}}}}
-{"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"tool_call","toolCallId":"call_00_twNfzWSJ9WJn8YeoGVIi1932","title":"bash","kind":"execute","status":"in_progress","rawInput":{"command":"printf 'HELLO\\n'"}}}}
+{"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"tool_call","toolCallId":"call_00_twNfzWSJ9WJn8YeoGVIi1932","title":"bash","kind":"other","status":"in_progress","rawInput":{"command":"printf 'HELLO\\n'"}}}}
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"tool_call_update","toolCallId":"call_00_twNfzWSJ9WJn8YeoGVIi1932","status":"failed","content":[{"type":"content","content":{"type":"text","text":"tool output rejected by codex policy: summarize instead"}}]}}}
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_thought_chunk","content":{"type":"text","text":"Every"}}}}
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_thought_chunk","content":{"type":"text","text":" attempt"}}}}
@@ -139,7 +139,7 @@
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_message_chunk","content":{"type":"text","text":" is"}}}}
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_message_chunk","content":{"type":"text","text":" working"}}}}
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_message_chunk","content":{"type":"text","text":":"}}}}
-{"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"tool_call","toolCallId":"call_00_xOnTckie072jHuPhX0Mz5115","title":"bash","kind":"execute","status":"in_progress","rawInput":{"command":"pwd"}}}}
+{"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"tool_call","toolCallId":"call_00_xOnTckie072jHuPhX0Mz5115","title":"bash","kind":"other","status":"in_progress","rawInput":{"command":"pwd"}}}}
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"tool_call_update","toolCallId":"call_00_xOnTckie072jHuPhX0Mz5115","status":"failed","content":[{"type":"content","content":{"type":"text","text":"tool output rejected by codex policy: summarize instead"}}]}}}
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_thought_chunk","content":{"type":"text","text":"It"}}}}
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_thought_chunk","content":{"type":"text","text":" seems"}}}}