perf(session): batch persisted turn-intent status reads

[beruro]

Summary

• add connection-scoped turn-intent insert/update helpers for atomic adjacent lifecycle writes
• add one batched persisted-status projection for reconnect/focus reconciliation
• preserve the existing turn-intent transition FSM and complete row shape

Why #512 was rewritten

The previous PR mixed RPC lifecycle, frontend async consumers, cache bounds, diagnostics, and profiling across 233 files. The clean pre-split head is preserved at junyu/pr-512-clean-backup-20260729. This PR is now the small persistence root of the stack; dependent CLI and frontend lifecycle PRs will target it separately.

Validation

• cargo test -p session_persistence turn_intents (12 passed)
• cargo check -p session_persistence
• rustfmt --edition 2021 --check crates/session-persistence/src/turn_intents.rs
• git diff --check origin/develop...HEAD

Architecture boundary

This PR only changes the authoritative SQLite turn-intent persistence boundary. It does not include CLI runner wiring, frontend reconciliation, generic async hooks, runtime caches, browser diagnostics, or Team Inbox (#531).

[beruro]

Split completed. The previous clean 233-file head remains recoverable at junyu/pr-512-clean-backup-20260729.

Review / merge order:

1. perf(session): batch persisted turn-intent status reads #512 — persisted turn-intent batch projection (1 file)
2. perf(cli): replace status polling with turn-intent push #565 — CLI runner + push reconciliation (depends on perf(session): batch persisted turn-intent status reads #512)
3. fix(session): preserve queue and terminal finality #566 — queue/intervention/finality semantics (depends on perf(cli): replace status polling with turn-intent push #565)

Independent async stack:

1. refactor(async): add scoped resource lifecycle #562 — scoped async lifecycle foundation (13 files)
2. refactor(data): scope async resource consumers #563 — scoped application consumers (depends on refactor(async): add scoped resource lifecycle #562)
3. perf(runtime): bound caches, scans, and background work #564 — bounded caches/scans/background work (depends on refactor(async): add scoped resource lifecycle #562; independent of refactor(data): scope async resource consumers #563)

Independent PRs:

• perf(diagnostics): bound RPC latency aggregation #567 — bounded RPC diagnostics (8 files)
• chore(runtime): add profiling contracts and audit gates #568 — profiling and typed transport contracts (29 files)

I also excluded 25 files that were byte-for-byte identical to running the current rustfmt on develop; they were formatter noise, not a reviewable semantic change. No split PR contains Team Inbox / #531 paths.