fix(setup): wire the agent-guard hook into settings.local.json, not settings.json

[AmirF194]

Summary

• The adopt flow commits the agent-guard PreToolUse wiring into the tracked .claude/settings.json while the script it invokes stays gitignored, which forced two prior workarounds for the same root cause (fix(agent-guard): make the PreToolUse hook a no-op until agent-guard.py is present #786, fix(agent-guard): make the fresh-clone hook guard cross-platform (Windows) #823).
• Moves the wiring into the gitignored, per-machine .claude/settings.local.json, written at the same moment the script is deposited, so the fresh-clone race that both workarounds guarded against no longer exists.
• Supersedes fix(agent-guard): make the fresh-clone hook guard cross-platform (Windows) #823 and retro-justifies removing the fix(agent-guard): make the PreToolUse hook a no-op until agent-guard.py is present #786 guard, per the issue.

Type of change

• Skill change (.claude/skills/<name>/): eval fixtures updated below
• Tool / bridge contract (tools/<system>/*.md)
• Python package (tools/*/ with pyproject.toml)
• Groovy reference impl
• Cross-cutting (RFC, AGENTS.md, sandbox, privacy-LLM)
• Documentation (docs/, README.md, CONTRIBUTING.md)
• Project template (projects/_template/)
• CI / dev loop (prek, workflows, validators)
• Other:

Test plan

• prek run --all-files passes
• For Python packages touched: uv run pytest / ruff check / mypy passes
• For Groovy bridges touched: command-line invocation tested end-to-end
• For skill changes: eval suite passes for the affected skill
• For skill behaviour changes: a new or updated eval fixture is included in this PR
• Other: ran the individual hooks by hand rather than prek run --all-files (installing prek's full tool set was not practical here): markdownlint-cli2 and typos on all 6 changed files (clean); skill-and-tool-validate run directly with PYTHONPATH against the stdlib-only validator package (0 hard failures, same 29 pre-existing soft warnings on unrelated skills, none on the touched files). Could not run the lychee link-check hook (its cargo install build ran the local disk near empty and was aborted); checked by hand instead that every link this diff adds or edits is an in-repo anchor (worktree-init.md#step-1d-..., adopt.md#step-10-..., adopt.md#step-12-..., ../../tools/agent-guard/README.md) and confirmed each target heading/file exists on this branch. Also extracted the diff's own idempotent-merge Python and ran it standalone against five fixtures (missing file, unrelated existing keys, already-wired no-op, hand-corrupted JSON, a second pre-existing Bash matcher) to confirm the merge behaves as described in each case. Checked docs/vendor-neutrality.md's inputs (**Vendor:** / **Harness:** fields in tools/agent-guard/README.md) are untouched by this diff, so the vendor-neutrality-score hook has nothing to regenerate.

RFC-AI-0004 compliance

• HITL: any new mutation is gated on explicit user confirmation
• Sandbox: no new unrestricted host access; network reach declared in the adapter
• Vendor neutrality: placeholders (<PROJECT>, <tracker>, <upstream>, <security-list>) used in all skill / tool prose (the check-placeholders prek hook is the mechanical gate)
• Conversational + correctable: agentic-override path documented if behaviour is adopter-tunable
• Write-access discipline: no autonomous outbound messages; drafts only, sent on confirmation
• Privacy LLM: private content does not reach a non-approved LLM; redactor invoked where needed

Linked issues

Fixes #824

Notes for reviewers

.gitignore already lists /.claude/settings.local.json as a base entry (Step 7), so nothing there needed to change; only the destination the docs point /magpie-setup at moved.

[AmirF194]

Flagging for whoever reviews this: #913 also touches the same "Hook wired in settings.json" bullet in verify.md (and a nearby line in worktree-init.md), as part of its broader adopt/install rename. Its edit there is a link-text rename only, not a fix for the issue this PR addresses, so I do not think it is a competing claim, but the two will conflict on merge and whichever lands second will need a rebase.

[AmirF194]

Thanks for the review. The red ruff format (workspace) check flags three files this PR does not touch (contributor-nomination/fetch.md, contributor-sentiment/SKILL.md, issue-reproducer/verification.md), so it looks like pre-existing drift rather than something introduced here. Happy to rebase once #1092 settles if that clears it.

[AmirF194]

Rebased onto main to resolve the conflict with #913 flagged above. Both bullets now point at install.md (the renamed file) while keeping the settings.local.json content from this PR. No other changes.

[AmirF194]

Found and fixed a leftover: the #913 rebase repointed two of the three adopt.md links in worktree-init.md to install.md, but missed the one inside the settings.local.json wiring bullet this PR adds. That was the actual cause of the prek and validate skills and tool contracts CI failures, not the pre-existing skill-line-limit warnings. Pushed 8b71010.