feat(naming-spec): @pgpmjs/naming-spec — PGPM naming spec v1 (derived change paths)

[pyramation]

Summary

New zero-dependency leaf package @pgpmjs/naming-spec: the PGPM naming spec as a pure projection. A change path is never authored and never identity — it is rendered on demand from an object's identity, so regrouping, renaming schemes, or repartitioning packages can never break identity-keyed consumers (diff, dependency resolution).

The reference implementation is constructive-db's db_deps SQL package (db_deps.table_deps, column_deps, procedure_deps, next_alteration, ...); this is the TypeScript rendering of the same spec, byte-for-byte compatible with the generated application/constructive plan.

• pathFor(identity, { style }) — total, deterministic:

  directory style (db_deps / generated plans, default):
    schemas/{s}/schema
    schemas/{s}/tables/{t}/table
    schemas/{s}/tables/{t}/columns/{n}/column
    schemas/{s}/tables/{t}/{constraints|policies}/{n}/{constraint|policy}
    schemas/{s}/tables/{t}/{triggers|indexes|fixtures}/{n}
    schemas/{s}/procedures/{n}/procedure     schemas/{s}/views/{n}/view
    extensions/{n}   roles/{n}
  flat style (hand-authored packages): drops the trailing kind token
  

• alterationPathFor(parent, n) — the conflict/re-alteration convention: <parent>/alterations/alt0000000042, mirroring db_deps.next_alteration (strips any existing suffix so a parent can be renumbered; the counter is caller state, rendering is pure).
• PGPM_NAMING_SPEC_VERSION = 1; ObjectIdentity declared structurally (identical to identityOf's output in pgsql-parser#326) — parsing stays in the parser repo, pgpm conventions stay here.

Verified no duplicate change names exist in any constructive-db pgpm.plan (the alt counter is what keeps it that way). Phase 1 of constructive-planning#1329; follow-ups: defaultChangeName delegates to identityOf+pathFor, and db-deps gains parity tests against this package.

Note: pnpm run lint fails identically in existing pgpm packages (ESLint 9 flat-config migration pending repo-wide) — not introduced here; tests and build pass.

Link to Devin session: https://app.devin.ai/sessions/562099f8b3d94877b5ab57ec8bb90bec
Requested by: @pyramation

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