#79 Make the skills more agent agnostic (trying to make claude and codex agreeing on them)

Make Goldener research skills usable across agents while retaining their research criteria, repository formats, and authorized delivery behavior. Instructions describe capabilities rather than specific interaction or connector APIs; each installable skill includes the resources it needs.

• Add the shared sync contract and its six generated standalone copies. Restore explicit relevance and identity checks, bibliography/researcher formats, source trust rules, worktree handling, branch/commit/PR naming, issue completion rules, and recovery after partial delivery. Imported ideas retain the existing Question / Date / Author / Context format with escaped source text and provenance in the run record and PR.
• Bundle the full paper-review workflow, template, and helper with short-paper-review, and add its target-format guide. skills/tools/bundle_resources.py regenerates these resources and derives marketplace descriptions from SKILL.md frontmatter, which is the source of truth.
• Use explicit, overridable budgets: 30 author checks, 200 abstract checks, and 300 network requests by default; theme pool/seed caps are also overridable. The three-paper qualification for discovered researchers and two-level recursion remain. Unresolved namesake ambiguity can require a question, now disclosed in the researcher description.
• For large unscoped lab lists, declare an eight-calendar-year window including the current year. Completing that window permits issue closure; the PR and issue outcome must identify the exact years and excluded older output. Explicit ranges and all-history requests override this default, and incomplete requested coverage keeps issues open.
• Keep Goldener's established non-profit, open-source positioning. Outreach uses neutral sender wording unless the user supplies a representative role. PR researcher lookup fetches the recorded head/base commits into a scratch object store and extracts only regular root/topic research documents, rejecting unsafe paths and symlinks.
• Fix Unicode title matching and validate explicit repository roots using the same markers as automatic discovery. Proposal reports include snapshot/retrieval provenance and explain any shortfall against the requested proposal count. Short summaries disclose AI generation by default, with the user override stated consistently in frontmatter and instructions.
• Merge current main, preserving Thunderbird signature handling and draft Date/Message-ID headers. Mailbox config returns 0 for success, 2 for absent/partial configuration, and 1 for errors; it resolves the password once, includes the signature source, preserves missing-env-file paths, and suppresses credential/provider details.

Validation: 16 local regression tests passed; all 10 skills passed the skill-creator validator; generated-resource/catalog checks, relative references in 19 Markdown files, and git diff --check passed. Tests use local fixtures and mocked mailbox/vault access; no live outreach or publishing workflows were executed.