Make issue-draft summaries compact and byte-budgeted

[Widthdom]

Summary

• Add a dedicated compact DTO for recipe/audit issue-draft summaries so full recipe definitions, rendered issue bodies, and source rows are not repeated.
• Enforce --max-json-bytes against the complete UTF-8 JSON document including its final newline, omitting only whole summary rows and returning typed E028 guidance when the envelope cannot fit.
• Preserve positive-query and evidence-path accounting across --limit / --total-limit, with explicit authority and lower-bound metadata plus uncapped recovery commands.
• Preserve the full issue-draft output contract and the invoked search versus audit identity.

Validation

• dotnet build CodeIndex.sln -c Release --no-restore -p:UseSharedCompilation=false — passed with 0 warnings and 0 errors on the final branch.
• dotnet test tests/CodeIndex.Tests/CodeIndex.Tests.csproj --no-restore --no-build --filter FullyQualifiedName~RunSearch_RecipeIssueDraft — 8/8 passed on both net8.0 and net9.0 after the final review fixes.
• Full Release suite on the implementation baseline — net8.0: 11,226 passed, 7 skipped; net9.0: 10,760 passed, 412 skipped; 0 failed.
• dotnet format CodeIndex.sln --verify-no-changes --no-restore — passed.
• dotnet run --project tools/CodeIndex.Changelog -- check — passed.
• The Issue Make issue-draft summary output genuinely compact and byte-budgeted #5058 reproduction now exits successfully within the 120,000-byte budget.
• Final cdidx index . --commits HEAD --json and cdidx status --check --json completed with 0 warnings/errors and a clean, current index.

Documentation and changelog

• Updated the English and Japanese sections of USER_GUIDE.md, DEVELOPER_GUIDE.md, and TESTING_GUIDE.md.
• Added bilingual fragment changelog.d/unreleased/5058.fixed.md, referencing Make compact output controls easier to discover and apply consistently across audit and recipe workflows #4064, Add compact metadata controls for audit issue-drafts output #4118, and Add compact bulk-triage modes for audit/search count and issue-draft outputs #4308.

Review

• Ran the repository-required Codex adversarial review for two rounds.
• Round 1 findings (bounded count semantics and missing testing documentation) were fixed.
• Round 2 findings (positive queries hidden by --total-limit and pre-limit evidence-path accounting) were fixed and covered by passing regression tests. The workflow's two-round review cap was respected.

Follow-ups

• None.

Fixes #5058