fix: restore thread id in get_review_comments response

[omid-ant]

Summary

Restore the thread id field to MinimalReviewThread so that pull_request_review_write with method: resolve_thread / unresolve_thread is actually usable.

Why

#2062 dropped id from the minimized review-thread output, noting it was "not used for any subsequent tool call". While this was true at the time, #1919 later added resolve_thread / unresolve_thread, both of which require a thread node ID. The tool's own docstring reads:

Get thread IDs from pull_request_read with method get_review_comments.

…but that tool no longer returns them, so there's no way to resolve a thread without leaving the MCP server. This results in callers of this tool being unable to resolve threads through the resolve_thread tool.

The GraphQL query (reviewThreadNode in pkg/github/pullrequests.go) already fetches ID — it's just dropped during minimization.

Also see: #2229

What changed

• Add ID string to MinimalReviewThread
• Populate it in convertToMinimalReviewThread via fmt.Sprintf("%v", thread.ID)

MCP impact

• No tool or API changes
• Tool schema or behavior changed — pull_request_read (get_review_comments) now includes id per thread
• New tool added

Prompts tested (tool changes only)

• "List the review threads on PR [docker] build arm64 #42 in owner/repo, then resolve the first one"

Security / limits

• No security or limits impact
• Auth / permissions considered
• Data exposure, filtering, or token/size limits considered — ~40 chars/thread ("id":"PRRT_kwDO…",), negligible impact on Reduce context usage for get_pull_request_review_comments using pull_request_read #2062's 14.5% savings

Tool renaming

• I am renaming tools as part of this PR (e.g. a part of a consolidation effort)
  • I have added the new tool aliases in deprecated_tool_aliases.go
• I am not renaming tools as part of this PR

Docs

• Not needed
• Updated (README / docs / examples)