#19621: feat: shared-bootstrap hook for cross-agent bootstrap files

## Summary New bundled hook that auto-discovers `SHARED_*.md` files from `<stateDir>/shared/` (default `~/.openclaw/shared/`) and injects them into every agent's Project Context during `agent:bootstrap`. - **Zero configuration** — no config entries, no schema changes. If the directory exists and contains `SHARED_*.md` files, they're injected. - **`SHARED_` prefix required** — only files matching `SHARED_*.md` are loaded, preventing confusion with per-workspace bootstrap files. - **Alphabetical ordering** — files are sorted and appended after workspace bootstrap files for deterministic injection order. - **No subagent filtering** — shared files appear in every session type (main, subagent, cron). The whole point is universal rules. - **Strict error handling** — missing directory is silent (feature not in use); unreadable directory or files throw (mismatched expectations if bootstrap proceeds without expected context). ## Motivation Multi-agent setups need shared rules, personas, and instructions across all agents without duplicating files per workspace. The existing `bootstrap-extra-files` hook restricts files to within the workspace directory and only loads recognized bootstrap basenames. This hook reads from an external well-known path (`STATE_DIR/shared/`) and accepts any `SHARED_`-prefixed `.md` filename. ## Usage ```bash mkdir -p ~/.openclaw/shared echo "# Shared Rules" > ~/.openclaw/shared/SHARED_RULES.md # restart gateway — every agent now gets SHARED_RULES.md in Project Context ``` ## Changes - `src/hooks/bundled/shared-bootstrap/handler.ts` — hook implementation (43 lines) - `src/hooks/bundled/shared-bootstrap/handler.test.ts` — 9 tests - `src/hooks/bundled/shared-bootstrap/HOOK.md` — hook metadata and documentation ## Design decisions - **Auto-discovery over config** — avoids schema modifications and keeps the feature dead simple. No `enabled`/`dir` config knobs. - **`SHARED_` prefix** — distinguishes shared files from per-workspace bootstrap files at a glance. - **`as WorkspaceBootstrapFile` cast** — `WorkspaceBootstrapFileName` is a narrow union of known names (`SOUL.md`, `AGENTS.md`, etc.). Shared files use custom names by design. The cast is localized and downstream `.name` usage is display/logging only. - **ENOENT vs other errors** — `readdir` catches only `ENOENT` (directory doesn't exist = feature not enabled). All other errors (permissions, I/O) propagate as fatal. Closes #19620 ## Test plan - [x] Does nothing when shared directory does not exist - [x] Does nothing when directory is empty - [x] Does nothing when no `SHARED_*.md` files present - [x] Injects `SHARED_*.md` files from shared directory - [x] Sorts files alphabetically - [x] Ignores files without `SHARED_` prefix - [x] Throws when shared directory exists but is unreadable - [x] Throws when a matching file cannot be read - [x] Shared files survive in subagent sessions <!-- greptile_comment --> <h3>Greptile Summary</h3> Adds a zero-config bundled hook that auto-discovers `SHARED_*.md` files from `~/.openclaw/shared/` and injects them into all agent bootstrap contexts. Clean implementation that follows existing bundled hook patterns (`bootstrap-extra-files`) with comprehensive test coverage (9 tests covering all documented behaviors). The type cast from custom `SHARED_*.md` names to `WorkspaceBootstrapFileName` is intentional and safe, as the `.name` field is only used for display/logging and map lookups downstream (verified in `system-prompt-report.ts:56-57`). Files are sorted alphabetically and appended after workspace bootstrap files. **Key behaviors:** - Silent no-op when directory doesn't exist (feature not enabled) - Throws on permission errors (strict error handling as documented) - Filters to only `SHARED_*.md` files - No subagent filtering (universal injection by design) <h3>Confidence Score: 5/5</h3> - Safe to merge with no concerns - Well-tested feature with 9 comprehensive tests covering all edge cases. Implementation follows established patterns from `bootstrap-extra-files` hook. Type cast is intentional and safe (documented in PR and code). Error handling is strict and appropriate. Zero-config design eliminates configuration issues. - No files require special attention _{Last reviewed commit: 42cd842} <!-- greptile_other_comments_section --> <!-- /greptile_comment -->