feat(claude-code-review): make checkout fetch-depth a caller input

[rekibnikufesin]

Summary

Adds an optional fetch_depth input (default 1, unchanged behavior) to ai-platform-claude-code-review.yml and wires it into the checkout step's fetch-depth, instead of the hardcoded 1.

Why

While migrating 0xPolygon/devops onto this shared workflow (approver mode), I found devops's existing inline review workflow set fetch-depth: 0 deliberately — added in devops#1589 by @Andres-Monje:

Full history. The review explicitly includes a "historical git context" pass, and without the base branch the reviewer cannot tell whether a claim about existing code still holds on main — a PR branched before a related fix gets reviewed against the pre-fix tree and reports issues that were already resolved.

This shared workflow's checkout was hardcoded to fetch-depth: 1, so every consumer using it (comment or approve mode) is missing that fix — the review can re-flag an issue elsewhere in a touched file that a since-merged commit on main already resolved, because a shallow checkout has no commit ancestry for the historical-context pass to walk.

Rather than change the default for everyone (some repos may prefer the faster shallow checkout and don't rely on the historical pass), this exposes it as a per-repo opt-in:

uses: 0xPolygon/pipelines/.github/workflows/ai-platform-claude-code-review.yml@<sha>
with:
  mode: approve
  fetch_depth: 0

Verification

• YAML re-parsed successfully after the edit (checked with Ruby's YAML loader, no repo tooling available locally for actionlint).
• No behavior change for existing consumers: default stays 1.
• devops will set fetch_depth: 0 in its caller once this merges and its pin is bumped (0xPolygon/devops#2086).

🤖 Generated with Claude Code

[claude]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.

[MaximusHaximus]

:engage: