fix: preserve cache errors and recover at capacity

[utpalsinghdev]

Summary

Closes #2229.

Cache errors now include their safe reason, and reads preserve the reason and limit returned by the host.

When the cache reaches its byte or entry limit, writes reclaim the oldest unleased values within the same transaction. Live loaders and values written by the current command are protected. If no safe eviction can make room, the write rolls back without changing existing values or publication fences.

Catalog reads recover when eviction removes parts referenced by a retained manifest. Storage and decoding errors remain errors rather than triggering rediscovery.

This update preserves current v2 limit diagnostics, retention clamping and combined catalog reads. Optional tool-name metadata is omitted if it would push the complete manifest over the entry limit. The apps version moves from 0.0.1-beta.79 to 0.0.1-beta.80.

Verification

Rebased onto v2 at edc9e5dc1301e251b168bdaca909cb27ec7d696a.

• Focused self-host tests: 25 passed, three filtered cases not executed.
• Coverage includes byte and entry pressure, cross-build eviction, live-loader rollback, partial catalog recovery, warm account-isolated reads and the oversized-manifest names fallback.
• Formatting, static checks, E2E registration, asset preparation, release checks, site build and links passed.
• Native Go tests passed: go test ./... in apps/hosted/self-host/native (ok executor.sh/self-host).
• Production Worker-size checks passed, with 16,651 bytes of API headroom, 0.3%.

Attached Cloud entry-count/cross-build checks were not run here. They need Cloudflare Artifacts credentials that this machine does not have.

app-cache-capacity.spec.ts
app-cache-limits.spec.ts
app-cache-evaluation.spec.ts
app-cache.spec.ts
app-cache-fences.spec.ts
app-cache-accounts.spec.ts
app-cache-stalled-loader.spec.ts
mcp-catalog.spec.ts
graphql-cache.spec.ts
cached-skills.spec.ts
provider-errors.spec.ts