feat: add support for rovodev

[awprice]

Summary

• Adds Rovo Dev as a first-class agent target, installable via rtk init --agent rovodev (project) or rtk init -g --agent rovodev (global).
• Inlines the RTK awareness content directly into AGENTS.md between <!-- rtk-instructions --> markers, using the existing upsert_rtk_block / remove_rtk_block helpers (Rovo Dev does not auto-expand @file references inside memory files, so the Codex-style @RTK.md indirection wouldn't work). Re-running rtk init is idempotent; uninstall removes only the RTK block and preserves any other user content.
• Bumps the supported-tools count from 13 → 14 in the README and adds a Rovo Dev section to hooks/README.md and hooks/rovodev/README.md.

Test plan

• cargo fmt --all && cargo clippy --all-targets && cargo test
  (1873 tests pass, including 3 new tests: test_try_parse_init_agent_rovodev, test_try_parse_init_agent_rovodev_global_uninstall, test_init_uninstall_dispatch_routes_rovodev_to_rovodev_cleanup — the last asserts the --global flag is forwarded to uninstall_rovodev).
• Manual testing:
  • rtk init --agent rovodev → writes <!-- rtk-instructions --> block into ./AGENTS.md.
  • Re-running → reports (already up to date) (idempotent).
  • Adding user content (e.g. # My Project ...) below the block, then rtk init --agent rovodev --uninstall → removes only the RTK block, preserves user content.
  • Global install/uninstall (-g) writes to / removes from ~/.rovodev/AGENTS.md.
• Verified acli rovodev run loads the inline block from AGENTS.md and the agent prefixes shell commands with rtk as instructed.

Files changed

• src/main.rs — new AgentTarget::Rovodev variant, install/uninstall dispatch wiring, 3 new tests
• src/hooks/init.rs — run_rovodev_mode (inline block via upsert_rtk_block) + uninstall_rovodev(global, ctx) (preserves user content via remove_rtk_block)
• src/hooks/constants.rs — ROVODEV_DIR constant (.rovodev)
• hooks/rovodev/{README.md,rtk-awareness.md} — embedded awareness doc (wrapped in <!-- rtk-instructions --> markers) and per-agent README
• README.md, hooks/README.md — supported-tools table and integration docs

Important: All PRs must target the develop branch (not master).
See CONTRIBUTING.md for details.

[CLAassistant]

All committers have signed the CLA.