fix: remove invalid show_tool_calls kwarg crashing Agent init (#157)

* fix: remove invalid show_tool_calls kwarg crashing Agent init (regression)

show_tool_calls was removed in f95c960 (Feb 26) because agno 2.5.x
doesn't accept it, then reintroduced in fd0ede0 (Mar 8) without
runtime testing — mocked tests hid the breakage.

Replace the bogus assertion with a regression guard and an allowlist
test that catches unknown kwargs before they reach production.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: auto-install git hooks, add black/isort to dev deps

- Add .githooks/ with portable pre-commit hook (macOS + Linux)
- make install now auto-activates hooks via core.hooksPath
- Add black and isort to poetry dev group (were only in CI via raw pip)
- Fix black formatting on 2 files flagged by CI
- Fix test_autoresearch_perplexity patching wrong module path

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Trip T <trip@local>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

pyproject.toml

@@ -69,6 +69,8 @@ pytest-timeout = ">=2.3.0"
 selenium = ">=4.20.0"
 pytest-randomly = "^4.0.1"
 pytest-xdist = "^3.8.0"
+black = ">=24.0.0"
+isort = ">=5.13.0"
 
 [tool.poetry.scripts]
 timmy = "timmy.cli:main"