feat(hooks): add OMP (Oh My Pi) agent support

[DavidHLP]

Summary

• Add rtk init --agent omp to install RTK transparent rewrite support for OMP (Oh My Pi) coding agent
• TypeScript extension loaded from hooks/pre/ that intercepts tool_call events and calls rtk rewrite for in-place command mutation — same architecture as the existing Pi extension
• Adds OMP as the 16th supported agent across README.md, hooks/README.md, and docs/guide/getting-started/supported-agents.md

Closes #591.

ℹ️ Note on #1365: This PR is an independent OMP implementation that supersedes #1365 (stale since June 2025). Both close #591. This PR uses --agent omp (consistent with Pi/Hermes/Droid) rather than #1365's --omp flag.

ℹ️ Conflict note for maintainers: This PR is intentionally left DIRTY (conflicting). The conflict is README.md only — develop reworded the "Supported AI Tools" intro while this PR bumped the count 15 → 16. Resolution: keep 16, adopt develop's wording (reducing the bash output the agent reads). The other two overlapping files auto-merge cleanly. develop was not merged into this branch to keep the commit history focused on the OMP feature.

---

Install / Uninstall

# Install
rtk init -g --agent omp          # global → ~/.omp/agent/hooks/pre/rtk.ts
rtk init --agent omp             # project → .omp/hooks/pre/rtk.ts

# Uninstall
rtk init --uninstall -g --agent omp   # global
rtk init --uninstall --agent omp      # project

# Preview
rtk init --agent omp --dry-run

Both install and uninstall honor the OMP_AGENT_DIR environment variable (mirrors PI_CODING_AGENT_DIR) for custom install locations.

---

Test plan

• cargo fmt --all --check — pass
• cargo clippy --all-targets — no issues
• cargo test — 2535 passed, 0 failed (14 new OMP tests)
• Manual testing: rtk init --agent omp install/uninstall/dry-run verified
• End-to-end: OMP 17.0.8 loads the extension and rewrites commands

Runtime evidence

Environment: rtk 0.42.4, omp 17.0.8, Linux x86_64.

1. rtk rewrite on OMP-rewritable commands:

$ rtk rewrite "git status"     → rtk git status
$ rtk rewrite "cargo test"     → rtk cargo test
$ rtk rewrite "ls ."           → rtk ls .
$ rtk rewrite "grep pattern ." → rtk grep pattern .
$ rtk rewrite "pytest"         → rtk pytest
$ rtk rewrite "ruff check"     → rtk ruff check

Exit code 1 (passthrough) for unsupported commands — correct.

2. Install (dry-run → real → file identity check):

$ rtk init --agent omp --dry-run
[dry-run] would create local OMP hooks/pre directory: .omp/hooks/pre
[dry-run] would create OMP extension: .omp/hooks/pre/rtk.ts
[dry-run] Nothing written.

$ rtk init --agent omp
RTK OMP extension installed:
  Extension: .omp/hooks/pre/rtk.ts

$ diff .omp/hooks/pre/rtk.ts hooks/omp/rtk.ts   # no diff — identical

3. Uninstall + idempotency:

$ rtk init --uninstall --agent omp
RTK uninstalled (OMP):
  - OMP extension: .omp/hooks/pre/rtk.ts

$ rtk init --uninstall --agent omp
RTK OMP extension was not installed (nothing to remove)

4. OMP loads the extension end-to-end:

$ rtk init --agent omp
$ omp -p --mode text --no-session "Run: git status"
Working...
On branch `feat/hooks-add-omp-agent-support`. One untracked path: `.omp/`.
Working tree is otherwise clean (no staged or modified files).

OMP called the extension, rtk rewrite turned git status → rtk git status, and the agent received compact filtered output instead of raw git status.

Note on UI screenshots: setLabel("RTK") and session_start status-line behavior (visible in OMP's TUI when rtk is missing) require a live interactive OMP TUI session — only CLI text evidence is included here.

---

Changes (8 files)

File	Change
src/hooks/constants.rs	OMP_DIR, OMP_LOCAL_DIR, OMP_HOOKS_PRE_SUBDIR, OMP_PLUGIN_FILE, OMP_AGENT_DIR_ENV
src/hooks/init.rs	resolve_omp_dir(), omp_plugin_path_for_scope(), ensure_omp_plugin_installed(), uninstall_omp(), run_omp_mode(), print_omp_result()
src/main.rs	Omp variant in AgentTarget, install/uninstall routing
hooks/omp/rtk.ts	TypeScript extension (new)
hooks/omp/README.md	Agent-specific docs (new)
README.md	Quick Start + agent table (16 tools)
hooks/README.md	Directory structure + agent table
docs/guide/getting-started/supported-agents.md	OMP section + table row

Design notes

• Same tool_call event + in-place mutation as Pi — shared extension API lineage (Earendil Works)
• Local interface declarations (no SDK import) for portability across OMP versions
• setLabel("RTK") + session_start status — persistent warning when rtk missing/too old (requested in feat(omp): add extension-based rewrite integration for Oh My Pi #1365)
• Hook-only — no AGENTS.md injection (transparent rewrite)

[CLAassistant]

All committers have signed the CLA.

[peterrauscher]

would love to see this!

[aancw]

Nice job, can't wait to see this implementation.

[thinhngotony]

I opened DavidHLP#1 with the OMP hook compatibility fixes: remove unsupported setLabel, mutate input for older runtimes, and return revised input for newer runtimes.

[DavidHLP]

Closing this in favor of #3707.

After reviewing the current state of things, #3707 is the better path forward:

• It follows the mutualization direction decided during the feat(omp): add extension-based rewrite integration for Oh My Pi #1365 review — no separate
  hooks/omp/ extension; OMP loads the exact hooks/pi/rtk.ts through its built-in
  legacy-pi-compat layer, so rewrite behavior stays byte-identical with Pi.
• It also supersedes feat(omp): add extension-based rewrite integration for Oh My Pi #1365 (with @makoMakoGo on board as co-author), closes Add support for Oh-My-Pi #591, and
  is already under active review with @KuSh.
• It additionally addresses runtime compatibility issues (guarded setLabel,
  returning revised input for newer runtimes) that also affected this PR — thanks to
  @thinhngotony for flagging those in fix(omp): support hook APIs across versions DavidHLP/rtk#1.

Thanks to @peterrauscher, @aancw and everyone who showed interest here — OMP support
is arriving, just via a shared-extension design instead of a standalone file. I'll be
testing #3707 against my OMP setup and contributing review feedback there as well.