fix(athena): harden council members — compaction recovery, block TodoWrite, analysis mode

- Add session.compacted handler in BackgroundManager to prevent premature
  task completion after compaction (defer first post-compaction idle)
- Explicitly block TodoWrite/TodoRead for council members in all sync
  points (AgentConfig permission + session tools + prompt instructions)
- Add council member prefix check to todo-continuation-enforcer skip list
  to prevent infinite continuation loops on completed council members
- Add optional analysis mode (solo/delegation) question to Athena setup:
  solo = thorough but heavier, delegation = fast via explore/librarian
- Allow call_omo_agent in council member allow-list for delegation mode
- Update COUNCIL_MEMBER_PROMPT with TodoWrite prohibition and delegation
  addendum for when delegation mode is selected
- Update prepare_council_prompt tool with mode parameter

src/agents/athena/council-member-agent.ts

@@ -22,10 +22,26 @@ export const COUNCIL_MEMBER_PROMPT = `You are an independent code analyst in a m
    - Where it is (file path, line number)
    - Why it matters (severity: critical/high/medium/low)
    - Your confidence level (high/medium/low)
-5. Be concise but thorough — quality over quantity`
+5. Be concise but thorough — quality over quantity
+
+## CRITICAL: Do NOT use TodoWrite
+- Do NOT create todos or task lists
+- Do NOT use the TodoWrite tool under any circumstances
+- Simply report your findings directly in your response`
+
+export const COUNCIL_DELEGATION_ADDENDUM = `
+## Delegation Mode
+You can delegate heavy exploration to specialized agents using call_omo_agent:
+- Use \`call_omo_agent(subagent_type="explore", ...)\` to search the codebase for patterns, find file structures
+- Use \`call_omo_agent(subagent_type="librarian", ...)\` for documentation lookups and external references
+- Always set \`run_in_background=true\` and collect results with \`background_output\`
+- Delegate broad searches, keep targeted reads for yourself
+- This saves your context window for analysis rather than exploration`
 
 export function createCouncilMemberAgent(model: string): AgentConfig {
-  // Allow-list: only read-only analysis tools. Everything else is denied via `*: deny`.
+  // Allow-list: only read-only analysis tools + optional delegation.
+  // Everything else is denied via `*: deny`.
+  // TodoWrite/TodoRead explicitly denied to prevent uncompletable todo loops.
   const restrictions = createAgentToolAllowlist([
     "read",
     "grep",
@@ -35,8 +51,14 @@ export function createCouncilMemberAgent(model: string): AgentConfig {
     "lsp_symbols",
     "lsp_diagnostics",
     "ast_grep_search",
+    "call_omo_agent",
   ])
 
+  // Explicitly deny TodoWrite/TodoRead even though `*: deny` should catch them.
+  // Built-in OpenCode tools may bypass the wildcard deny.
+  restrictions.permission.todowrite = "deny"
+  restrictions.permission.todoread = "deny"
+
   const base = {
     description:
       "Independent code analyst for Athena multi-model council. Read-only, evidence-based analysis. (Council Member - OhMyOpenCode)",