feat(agents): add Hephaestus - autonomous deep worker agent (#1287)

* refactor(keyword-detector): split constants into domain-specific modules

* feat(shared): add requiresAnyModel and isAnyFallbackModelAvailable

* feat(config): add hephaestus to agent schemas

* feat(agents): add Hephaestus autonomous deep worker

* feat(cli): update model-fallback for hephaestus support

* feat(plugin): add hephaestus to config handler with ordering

* test(delegate-task): update tests for hephaestus agent

* docs: update AGENTS.md files for hephaestus

* docs: add hephaestus to READMEs

* chore: regenerate config schema

* fix(delegate-task): bypass requiresModel check when user provides explicit config

* docs(hephaestus): add 4-part context structure for explore/librarian prompts

* docs: fix review comments from cubic (non-breaking changes)

- Move Hephaestus from Primary Agents to Subagents (uses own fallback chain)
- Fix Hephaestus fallback chain documentation (claude-opus-4-5 → gemini-3-pro)
- Add settings.local.json to claude-code-hooks config sources
- Fix delegate_task parameters in ultrawork prompt (agent→subagent_type, background→run_in_background, add load_skills)
- Update line counts in AGENTS.md (index.ts: 788, manager.ts: 1440)

* docs: fix additional documentation inconsistencies from oracle review

- Fix delegate_task parameters in Background Agents example (docs/features.md)
- Fix Hephaestus fallback chain in root AGENTS.md to match model-requirements.ts

* docs: clarify Hephaestus has no fallback (requires gpt-5.2-codex only)

Hephaestus uses requiresModel constraint - it only activates when gpt-5.2-codex
is available. The fallback chain in code is unreachable, so documentation
should not mention fallbacks.

* fix(hephaestus): remove unreachable fallback chain entries

Hephaestus has requiresModel: gpt-5.2-codex which means the agent only
activates when that specific model is available. The fallback entries
(claude-opus-4-5, gemini-3-pro) were unreachable and misleading.

---------

Co-authored-by: justsisyphus <justsisyphus@users.noreply.github.com>

src/hooks/AGENTS.md

@@ -1,14 +1,22 @@
 # HOOKS KNOWLEDGE BASE
 
 ## OVERVIEW
-32 lifecycle hooks intercepting/modifying agent behavior. Events: PreToolUse, PostToolUse, UserPromptSubmit, Stop, onSummarize.
+
+34 lifecycle hooks intercepting/modifying agent behavior across 5 events.
+
+**Event Types**:
+- `UserPromptSubmit` (`chat.message`) - Can block
+- `PreToolUse` (`tool.execute.before`) - Can block
+- `PostToolUse` (`tool.execute.after`) - Cannot block
+- `Stop` (`event: session.stop`) - Cannot block
+- `onSummarize` (Compaction) - Cannot block
 
 ## STRUCTURE
 ```
 hooks/
-├── atlas/                      # Main orchestration (752 lines)
+├── atlas/                      # Main orchestration (757 lines)
 ├── anthropic-context-window-limit-recovery/ # Auto-summarize
-├── todo-continuation-enforcer.ts # Force TODO completion (16k lines)
+├── todo-continuation-enforcer.ts # Force TODO completion
 ├── ralph-loop/                 # Self-referential dev loop
 ├── claude-code-hooks/          # settings.json compat layer - see AGENTS.md
 ├── comment-checker/            # Prevents AI slop
@@ -37,6 +45,8 @@ hooks/
 ├── category-skill-reminder/    # Reminds of category skills
 ├── empty-task-response-detector.ts # Detects empty responses
 ├── sisyphus-junior-notepad/    # Sisyphus Junior notepad
+├── stop-continuation-guard/    # Guards stop continuation
+├── subagent-question-blocker/  # Blocks subagent questions
 └── index.ts                    # Hook aggregation + registration
 ```
 
@@ -51,7 +61,7 @@ hooks/
 
 ## EXECUTION ORDER
 - **UserPromptSubmit**: keywordDetector → claudeCodeHooks → autoSlashCommand → startWork
-- **PreToolUse**: questionLabelTruncator → claudeCodeHooks → nonInteractiveEnv → commentChecker → directoryAgentsInjector → directoryReadmeInjector → rulesInjector → prometheusMdOnly → sisyphusJuniorNotepad → atlasHook
+- **PreToolUse**: subagentQuestionBlocker → questionLabelTruncator → claudeCodeHooks → nonInteractiveEnv → commentChecker → directoryAgentsInjector → directoryReadmeInjector → rulesInjector → prometheusMdOnly → sisyphusJuniorNotepad → atlasHook
 - **PostToolUse**: claudeCodeHooks → toolOutputTruncator → contextWindowMonitor → commentChecker → directoryAgentsInjector → directoryReadmeInjector → rulesInjector → emptyTaskResponseDetector → agentUsageReminder → interactiveBashSession → editErrorRecovery → delegateTaskRetry → atlasHook → taskResumeInfo
 
 ## HOW TO ADD