refactor(pi): unify config format and add pi-agent execution layer

[FradSer]

What

Refactor the pi plugin to unify its configuration format and add a dedicated execution layer.

• Named-endpoint config: delegate, review, and setup now share the same endpoint-first settings format (endpoints / defaultEndpoint / defaultModel), with legacy flat fields kept as a fallback.
• pi:pi-agent execution layer: all pi CLI runs go through a dedicated agent that builds the command as an array (zsh-safe), runs it in the background, and verifies the real outcome — delegate checks git diff --stat, review returns pi's stdout.
• Worktree isolation: AGENT_DIR / PI_CODING_AGENT_DIR keeps pi state inside the project, and models.json merges idempotently (baseUrl + model registration, skip when unchanged) to avoid out-of-worktree writes.
• THINKING default → max: all config defaults now use the highest thinking level.
• Shared-scope guard: --edit-config --shared warns that apiKey must be a $ENV_VAR reference (tracked file, no literal secrets).
• Version: 0.1.3 → 0.2.0 (adds a new agent).

Why

• Previously delegate and review read different config formats, so a single .claude/pi.local.json could configure one but not the other.
• pi's real output is file edits (delegate) or stdout (review); a dedicated execution layer keeps the main context clean and verifies the actual outcome.
• In git-worktree/sandboxed sessions, writing $HOME/.pi is rejected; the agent-dir redirection fixes that.

Validation

• validate-plugin.py pi → PASSED (no issues)
• E2E: config reading resolves identically across endpoint and flat formats; models.json merge is idempotent; array-built pi command runs with no "Model not found" warning; pi returns OK through the local proxy.

Notes

• Target branch main (default branch). No open issues are linked.
  🤖 Generated with Claude Code

[code-terrier]

Code Terrier Review: primary reviewer failed

The primary model gateway-compat|dynamic/deepseek-v4-flash did not complete, so no review was published for this commit.

The primary is the verifier and publish identity for a review — without it, any findings the
other models produced would go out unverified, and an empty result would read as "no issues"
when the truth is "the main reviewer never ran". Failing loudly is deliberate.

• Primary: gateway-compat|dynamic/deepseek-v4-flash
• Other reviewers that did finish: 1

Failure detail

ReviewerError: pi review error: pi exited 0 without calling its terminating tool: {"input":0,"output":0,"cacheRead":0,"cacheWrite":0,"total":0}},"stopReason":"error","timestamp":1786255198389,"responseId":"6091d242-f6fb-4ad7-81cd-337c6eaf658f","responseModel":"deepseek-v4-flash","errorMessage":"Stream ended without finish_reason"}],"willRetry":false}
{"type":"auto_retry_end","success":false,"attempt":3,"finalError":"Stream ended without finish_reason"}
{"type":"agent_settled"}

Push a new commit (or re-run the review) once the underlying cause is resolved.

[code-terrier]

Code Terrier Review: primary reviewer failed

The primary model gateway-compat|dynamic/deepseek-v4-flash did not complete, so no review was published for this commit.

The primary is the verifier and publish identity for a review — without it, any findings the
other models produced would go out unverified, and an empty result would read as "no issues"
when the truth is "the main reviewer never ran". Failing loudly is deliberate.

• Primary: gateway-compat|dynamic/deepseek-v4-flash
• Other reviewers that did finish: 1

Failure detail

ReviewerError: pi review error: pi exited 0 without calling its terminating tool: {"input":0,"output":0,"cacheRead":0,"cacheWrite":0,"total":0}},"stopReason":"error","timestamp":1786262628256,"responseId":"b70961dd-1a10-40ba-b075-5f13addd0234","responseModel":"deepseek-v4-flash","errorMessage":"Stream ended without finish_reason"}],"willRetry":false}
{"type":"auto_retry_end","success":false,"attempt":3,"finalError":"Stream ended without finish_reason"}
{"type":"agent_settled"}

Push a new commit (or re-run the review) once the underlying cause is resolved.

[FradSer]

@code-terrier review

[FradSer]

@code-terrier review

[FradSer]

@code-terrier review

[FradSer]

@code-terrier review

[code-terrier]

Code Terrier reviewed the changes — no issues found. ✅