[B2] Cleanup: stale catch-all comment and legacy hydration markers (audit O1/O2)

[SisyphusZheng]

Non-blocking observations from the B1.1 hostile admission audit (#1222, report docs/evidence/2026-09-03-v044-hostile-admission-audit.md):

• O1: packages/app/src/route-manifest.ts:34 documents catch-all as /products/* while the tested behavior is /products/:slug{.+} (route-manifest.test.ts:144). Stale source comment.
• O2 (D13): legacy hydration markers and the public DATA_SSR_PROPS re-export outlive their removed channel. Record their status at re-baseline; remove or document with removal condition.

Not Beta.1 blockers (no §4.3 failure). Part of #1155.

[SisyphusZheng]

Closed by PR #1310 (squash-merged to dev). O1: stale catch-all comment corrected in packages/adapter-vite/src/route-manifest.ts (actual Hono named-regex semantics /products/:slug{.+}, matching the pinned test). O2/D13: legacy hydration markers REMOVED with zero-consumer proof — DATA_SSR_PROPS public re-export deleted, DATA_SIGNAL*/DATA_EID/BRANCH_MARKER_PREFIX/FOR_ITEM_* + parseSignalAttrSpec deleted; DATA_OE_LIGHT kept as the live ADR-0142 charter. Packed-artifact anti-regression gate added (FORBIDDEN_LEGACY_PATHS + FORBIDDEN_LEGACY_SOURCE_PATTERNS in package-artifacts:check, ci+release tiers). Broader v0.43 residue audit (stage risk #8): 5 dead modules deleted (types.ts ElementDefinition, vnode.ts, prop.ts, dom-utils.ts, dsd-shadow-root.ts) + legacy DSD-pipeline interfaces from render.ts; kept-with-proof items documented in the PR body. interface-snapshot regenerated: DATA_SSR_PROPS the sole public delta; packed element tarball loses exactly the 5 modules.