v1.8.2: tool loop cap-hit summary + tool call UI compaction

Old hardcoded MAX_TOOL_LOOP_DEPTH=15 replaced by per-agent
max_tool_calls (1-100, AGENTS.md frontmatter) with defaults: 30 for
read-only-only agents, 10 for agents that include any non-read-only
tool, 15 for raw chat. When the loop hits cap, fire one final summary
call with tools disabled, stream the wrap-up into the in-flight
assistant message, then insert a system sentinel with
metadata.kind='cap_hit'. The sentinel renders an amber bubble with a
Continue button (latest sentinel only) that POSTs to a new
/api/chats/:id/continue route to extend. Hard ceiling: 3 cap-hits per
chat (2 continues max) — third sentinel reports can_continue=false.

Error frames carry a machine-readable reason code alongside human
error text. Failed messages persist the reason via
metadata.kind='error' so the bubble renders specifics on reload (WS
error frame is one-shot).

Tool call UI rewired: ToolCallLine renders inline (↳ name args
spinner/check/✗, expand-on-tap for args+result); ToolCallGroup
collapses 3+ consecutive same-tool runs into a compact card.
MessageList owns a three-pass pre-render (flatten + fold tool
results onto matching runs by id + group same-tool runs + number
sentinels). MessageBubble drops tool rendering and adds the
sentinel / error-reason branches. ToolCallCard deleted.

Roadmap follow-up logged: add explicit max_tool_calls: 30 to the 6
agents in /data/AGENTS.md and /opt/boocode/AGENTS.md post-ship for
discoverability (defaults handle behavior identically).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/server/src/schema.sql

@@ -158,3 +158,10 @@ END $$;
 -- the DB; they live in builtins (services/agents.ts) and a per-project AGENTS.md.
 -- agent_id is the slugified agent name. NULL means "use BooCode defaults".
 ALTER TABLE sessions ADD COLUMN IF NOT EXISTS agent_id TEXT;
+
+-- v1.8.2: per-message metadata for sentinels (cap-hit) and structured error
+-- reasons. JSONB so future kinds can extend without further schema churn.
+-- Shape for cap_hit:  { kind: 'cap_hit', used: number, limit: number,
+--                       agent_name: string|null, can_continue: boolean }
+-- Shape for errors:   { error_reason: 'llm_provider_error'|..., error_text: string }
+ALTER TABLE messages ADD COLUMN IF NOT EXISTS metadata JSONB;