feat(review): anchor-safety validation drops un-commentable suggested changes

[JSONbored]

Guard the suggested-change surface against GitHub 422s: drop the suggestion (but keep the finding as a plain comment) when its target line isn't a commentable RIGHT-side diff line. The finding's own line already goes through rightSideLinesFromPatch; this slice makes the suggestion respect the same set and fail-safe.

Deliverables

• In selectInlineComments (src/review/inline-comments.ts:79) validate the suggestion's anchor against the file's rightSideLinesFromPatch set; strip the suggestion (not the whole comment) when un-anchorable
• Never emit a suggestion on a file with no usable patch
• Preserve the existing per-line dedupe + MAX_INLINE_COMMENTS cap
• Tests: anchorable → suggestion kept; un-anchorable → comment kept, suggestion dropped, no 422 shape; empty patch file

References

• src/review/inline-comments.ts:49
• src/review/inline-comments.ts:79
• src/review/inline-comments.ts:90
• part of #1956

Part of #1956.

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size: S · held for later release (gittensor:feature once activated)

[linear-code]

JSO-2242