feat(miner-foundation): MinerGoalSpec type definitions for .gittensory-miner.yml

[JSONbored]

Define the TypeScript type surface for the MinerGoalSpec — the per-repo config a maintainer/repo-owner drops as .gittensory-miner.yml to tell a miner what to look for and how to behave when targeting their repo. This issue is types-only (the parser is a separate follow-up issue), analogous to how src/signals/focus-manifest.ts's FocusManifest type is defined ahead of/alongside its parser. Scope the fields to what the phase's existing .gittensory.yml already models for the REVIEW side (wantedPaths, blockedPaths, preferredLabels, linkedIssuePolicy, issueDiscoveryPolicy) plus miner-specific additions the roadmap implies are needed (a max-concurrent-claims-per-repo cap, an opt-in/opt-out flag since a repo owner may not want autonomous miners targeting them at all, and a pointer to which lanes/labels a miner should prefer) — keep the field list intentionally small for this foundation phase; it is easy to add fields later, hard to remove ones a contributor already started relying on.

Deliverables

• packages/gittensory-engine/src/miner-goal-spec.ts (or src/signals/miner-goal-spec.ts if the team prefers keeping config-schema types alongside focus-manifest.ts rather than in the engine package — pick whichever the reviewing maintainer confirms, defaulting to the engine package per the phase's "shared logic lives in gittensory-engine" principle) exporting a MinerGoalSpec type with: minerEnabled: boolean (default true — explicit opt-out, not opt-in, since a public repo with no file should still be minable by default, mirroring .gittensory.yml's own "safe by default" stance), wantedPaths: string[], blockedPaths: string[], preferredLabels: string[], maxConcurrentClaims: number (a sane default, e.g. 1), issueDiscoveryPolicy: "encouraged" | "neutral" | "discouraged".
• A DEFAULT_MINER_GOAL_SPEC constant with the safe defaults, analogous to how focus-manifest.ts documents each field's default in a comment.
• JSDoc on every field, matching the density and "Default: X" comment convention used throughout .gittensory.yml.example.
• No parsing logic yet — this issue is the type contract only; a unit test simply asserts DEFAULT_MINER_GOAL_SPEC type-checks against MinerGoalSpec and that every field has a documented default in a co-located comment (a lightweight "every field is documented" lint-style test, not full parser coverage).

References

• src/signals/focus-manifest.ts (FocusManifest type family, and its gate/features/review sub-configs) — the type-shape precedent to mirror in spirit (small typed config object with an explicit defaults constant).
• .gittensory.yml.example (wantedPaths, blockedPaths, preferredLabels, linkedIssuePolicy, issueDiscoveryPolicy fields, lines 30-80) — the exact field names/semantics to carry over from the review-side manifest where they overlap.
• New path: .gittensory-miner.yml (the file this type models) and its type-definition module (path TBD per the note above).

[linear-code]

JSO-2390