refactor(code-nav): consume codeIndexState, drop deprecated indexingStatus

[jlitola]

Summary

Defensive swap from indexingStatus: IndexingStatus (backend-@deprecated) to codeIndexState: CodeIndexState across every code-navigation GraphQL result we read. Same shape as PR #22 (pkg deps typed fields): read the non-deprecated field while the legacy one is still served, so the CLI keeps working when the backend eventually removes it.

What changed on the wire

Before	After
searchSymbols { … indexingStatus }	searchSymbols { … codeIndexState }
listRepoFiles { … indexingStatus }	listRepoFiles { … codeIndexState }
fetchCodeContext { … indexingStatus }	fetchCodeContext { … codeIndexState }
grepRepoFile { … indexingStatus }	grepRepoFile { … codeIndexState }

Enum mapping

IndexingStatus (old)	CodeIndexState (new)	Notes
INDEXED	CURRENT	Happy path — same semantics
—	STALE	New: results served but a reindex is enqueued. We treat as happy-path, same as CURRENT.
INDEXING	INDEXING	Same string, same sentinel-promotion logic
PENDING	PENDING	Unchanged
FAILED	FAILED	Unchanged
NOT_FOUND	NOT_FOUND	Unchanged
UNRESOLVABLE	UNRESOLVABLE	Same string, same sentinel check

The CLI's two string checks (`=== "INDEXING"` and `=== "UNRESOLVABLE"`) fire on identical values in both enums — no behavioural change.

Scope

• 4 Zod schemas renamed.
• 4 GraphQL queries select `codeIndexState` instead of `indexingStatus`.
• `throwIfIndexing` helper's input-type field renamed; two inline sentinel reads in `searchSymbols` mapping renamed.
• Test fixtures migrated:
  • `indexingStatus: "INDEXED"` → `codeIndexState: "CURRENT"` (18 fixtures)
  • `indexingStatus: "INDEXING"` → `codeIndexState: "INDEXING"` (5 fixtures)
• Two response-builder doc comments updated to reference the new field.

No envelope shape change. `codeIndexState` is consumed internally — never surfaced on any tool's envelope. `STALE` flows through identically to `CURRENT` today; future UX work could surface an "index being refreshed" note under `--verbose`, but that's a separate ticket.

Testing

• 1326 tests pass (`bun test`).
• Typecheck / lint / build clean.

Live-smoke (production pkgseer)

All four indexing-gated tools verified on `npm:express`:

• `code files npm:express lib --limit 3` — resolves paths, `CURRENT` flows as happy-path.
• `code read npm:express lib/express.js --lines 1-3` — returns bytes.
• `code grep npm:express middleware lib/express.js` — returns matches.
• `code search npm:express Router --json --wait 30` — `INDEXING` → retry promotes to typed error as before; resolves on second attempt with 2 results.

Test plan

• `bun test` passes (1326 / 0)
• `bun run typecheck` / `bun run build` / `bun run lint` clean
• Live-smoke every indexing-gated tool against production pkgseer
• No remaining references to `indexingStatus` in consumed code (grep-clean)

🤖 Generated with Claude Code