Add Claude Code hooks: marina hooks install

[danfry1]

Summary

marina's agent awareness (launchers, sessions, port leases) only took effect when someone ran a command. marina hooks install wires it into every Claude Code session:

event	what the agent gets
SessionStart	This project's running dev servers ("reuse them rather than starting duplicates"), its existing marina port, and counts of other/orphaned servers.
PreToolUse (Bash)	Only for dev-server starts (pnpm dev, npm run dev, vite, cargo run, …): a note if this project's server is already running, or if the command hard-codes a port that belongs elsewhere. Context only.
SessionEnd	The servers that session started are stopped (not on /clear or /resume). Opt out with --no-cleanup.

marina hooks install            # user settings (honours CLAUDE_CONFIG_DIR); --project for .claude/settings.json
marina hooks status
marina hooks uninstall

Design notes

• No permission decision is ever returned. permissionDecision: "allow" would silently auto-approve the command and ask/defer change behaviour; the docs don't state whether additionalContext works without a decision, so this was verified empirically (below).
• Fast path: the PreToolUse hook runs on every Bash call; non-matching commands return in ~20ms without building a snapshot.
• Timeouts: each hook sets its own (SessionEnd defaults to a 1.5s budget, too short to stop a server).
• Never in the way: hooks always exit 0; problems go to stderr (Claude's debug log).
• Settings safety: key order preserved (serde_json/preserve_order — indexmap was already in the tree), marina's entries identified by their command, user hooks untouched, malformed files refused, atomic writes, one-time settings.json.marina-bak; uninstall restores the original structure.
• Session-start never creates a port lease (read-only lookup).

Testing

• cargo fmt --check, clippy -D warnings, cargo test: 136 tests (9 new) — dev-server command detection (incl. a documented harmless false positive), hard-coded port parsing, context text for duplicates / foreign ports / silence, session-target matching, idempotent install preserving key order and user hooks, --no-cleanup, exact-restore uninstall, malformed settings refused, CLI usage errors.
• Live, with Claude's hook JSON on stdin: /clear and another session's end leave a server alone; the owning session's end stops exactly its server. Install/status/uninstall against a throwaway CLAUDE_CONFIG_DIR restored the file exactly; a malformed file was refused untouched.
• End-to-end in real Claude Code (one headless Haiku run, project-scoped hooks in a scratch dir): the model reported both the SessionStart context and the PreToolUse note delivered next to the Bash result, and the allowed echo ran normally — confirming context-without-decision works and leaves permissions unchanged. The headless session's own SessionEnd left the other session's server running.