fix(install): fire the search nudge on Claude Code's Grep tool, not just Bash (#1986)

ee1df22 narrowed the Claude Code search-guard matcher from "Glob|Grep" to
"Bash" on the premise that dedicated search tools were removed and searches
go through Bash. Current Claude Code routes content search through its
first-class Grep tool (its Bash tool description actively steers away from
shell grep), so the graphify-first nudge never fired on the agent's primary
exploration path and the graph was silently bypassed.

Three-part fix, per the issue's analysis:

- Matcher: "Bash" -> "Bash|Grep" in _claude_pretooluse_hooks. Glob already
  fires the read nudge via "Read|Glob", so Grep was the only orphaned tool.
- Guard body: the hook-guard search branch only inspected tool_input.command,
  which a Grep call doesn't carry (it has pattern/path/glob). A Grep-shaped
  input (pattern present, no command) is now treated as a search — it IS one
  by definition — and nudges whenever a fresh graph exists. The Bash
  token-matching path is unchanged, and a command-carrying input never
  triggers the Grep shape, so non-search Bash calls stay silent.
- Idempotency: "Bash|Grep" added to the four install/uninstall dedup filters
  (claude + codebuddy), so upgrading replaces the stale "Bash" hook in place
  instead of appending a duplicate — verified against a pre-fix settings.json.

Tests: new regression tests feed Grep-shaped tool_input through
hook-guard search and assert the nudge (with graph), silence (without),
valid PreToolUse JSON, and no blocking; plus a guard that a non-search Bash
command with a stray pattern key does not nudge. Existing matcher assertions
updated across test_search_hook/test_install/test_claude_md/test_codebuddy/
test_hook_strict. Hook+install suites: 397 passed. Full suite: 3224 passed;
the 13 failures are pre-existing on clean v8 in this environment.

Fixes #1986

tests/test_codebuddy.py

@@ -98,7 +98,7 @@ def test_codebuddy_install_hook_has_bash_matcher(tmp_path):
     codebuddy_install(tmp_path)
     settings = json.loads(_settings_path(tmp_path).read_text())
     hooks = settings["hooks"]["PreToolUse"]
-    bash_hooks = [h for h in hooks if h.get("matcher") == "Bash"]
+    bash_hooks = [h for h in hooks if h.get("matcher") == "Bash|Grep"]
     assert any("graphify" in str(h) for h in bash_hooks)