…hic API

Pull adapter-specific knowledge out of `service/stream.rs`. Previously
the stream service hardcoded Codex chunk-shape lookups (`payload.name`,
`payload` cloning, RFC 3339 timestamp parsing) and used two extraction
methods with different return types (`Vec<ExtractedFileChange>` vs
`Vec<TranscriptFileChange>`), so the call site had to reach into chunk
internals to fill in tool_name / tool_input / timestamp.

The trait now exposes two symmetric methods returning the same
`FileChangeRecord` type:

  fn file_changes_from_hook(&self, tool, input, ts) -> Vec<FileChangeRecord>
  fn file_changes_from_transcript(&self, chunk, fallback_ts)
      -> Vec<FileChangeRecord>

Each adapter overrides at most one. Defaults return empty. The
`FileChangeRecord` carries everything the persistence layer needs
(change, tool_name, tool_input, timestamp), so `stream.rs` just
iterates and inserts — no chunk shape knowledge anywhere outside the
adapter that owns that format.

Claude path is preserved bit-for-bit against main:

* `is_file_modifying` gate around the hook-extract loop is kept, so
  Read/Glob/etc. skip the call entirely (matches main's
  `if is_file_modifying_tool { ... }`).
* New `provides_transcript_file_changes()` capability flag (default
  false) gates the per-line transcript-extract loop. Claude returns
  false → the `file_changes_from_transcript` method is never invoked
  for Claude transcript lines, exactly as on main where no equivalent
  call existed.
* `file_changes_from_hook` for Claude wraps the same Write/Edit logic
  that lived in `extract_file_change` on main; the resulting DB writes
  have identical fields and timestamps (record.timestamp = req.timestamp).

CLI: replace the hardcoded `match agent.as_str() { "claude-code" => ...,
"codex" => ... }` in `main.rs` with `adapter.display_name()` and
`adapter.hooks_install_path()` from the trait, so adding a new agent
no longer requires touching the print-message code.

Codex: `file_changes_from_transcript` now resolves the chunk's RFC 3339
timestamp internally and returns it in each record, replacing the
duplicated timestamp logic that previously lived in `stream.rs`.
The `provides_transcript_file_changes` override is `true`.

Tests: 51 adapter tests (was 50), including a new fallback case
verifying that a chunk with no top-level timestamp falls back to the
hook delivery time. All hook/transcript extraction tests updated to
the new method names and return type.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

…ing --agent

Move the "claude"/"claude-code" alias resolution and dedup off the CLI and
onto the AgentAdapter::name() canonical id — the registry already maps both
strings to the same adapter, so the manual match was redundant. Dedup now
runs against the adapter's own id, not the user-provided string.

Change semantics: --agent codex installs only Codex hooks. Claude Code is
installed only when --agent is omitted entirely (default), instead of being
appended unconditionally to every --agent invocation. .gitignore entries are
derived from each installed adapter's hooks_install_path(), so a codex-only
init no longer pins .claude/settings.json into the ignore list.

Multi-agent split caused subtle drift on the Claude code path. Restore
parity with pre-multi-agent main:

- wire_protocol_version() trait method (default v2); Claude overrides
  to v1 so request bytes match main
- persists_model_without_usage() capability flag (default false); Codex
  sets it true. Server stream gate becomes
  has_tokens || (flag && model.is_some()), so Claude's update_tokens
  stays token-presence-only as in main
- ClaudeCodeAdapter parser locks onto first tool_use block via
  seen_tool_use flag (matches main's arr.iter().find() semantics)
- CLI stream uses adapter.wire_protocol_version() / adapter.name() for
  protocol_version + tool fields
- init.rs installs hooks after .gitignore update (matches main order)

Also: CLI init prints actually-installed gitignore entries instead of
hardcoded paths, and a comment marks _event_type as unused (routing is
via hook_event_name from stdin).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

…E with --agent semantics

Codex Stop hook entry was missing the `matcher` field that all other
lifecycle hooks (SessionStart, PreToolUse, PostToolUse) already carry,
risking a silent no-op if Codex requires the field. README also still
described `--agent` as additive ("in addition to the Claude Code hooks")
even though the flag has been replacement-only since 6fad80f.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>