feat(cli): emit per_node.db in recce init --cloud [PR 2/3]

[even-wei]

PR checklist

• Ensure you have added or ran the appropriate tests for your PR.
• DCO signed

What type of PR is this?

feat — wires the emitter into recce init --cloud and adds the cache.db handling.

What this PR does / why we need it:

Stacked on top of #1334 (PR 1/3 — the pure emitter module). Please review #1334 first; this PR shows the merge diff against that branch.

Wires PerNodeDbWriter from #1334 into recce init --cloud:

• After build_full_cll_map() succeeds, emits per_node.db for both base and current envs from the loaded manifests + catalogs
• Uploads per_node.db via a new per_node_db_url presigned-URL key (graceful-degraded: missing key logs a warning, doesn't fail the command)
• Cloud mode's cll_cache.db now lives in tempfile.mkdtemp(prefix="recce-cll-") instead of ~/.recce/cll_cache.db. Purpose: keep the warm-cache perf (build_full_cll_map re-uses previous CLL slices) while guaranteeing the cache DB never ends up on S3 or on the ECS task host after shutdown
• Removed the cloud-mode cll_cache_upload_url upload path entirely (cache.db is not a cloud artifact)
• shutil.rmtree cleanup of the tempdir on success via try/finally

Local (non-cloud) recce init behavior is unchanged: still writes ~/.recce/cll_cache.db (or whatever --cache-db points to), still doesn't emit per_node.db.

Which issue(s) this PR fixes:

Part of DRC-3295 (epic DRC-3294, project "Lineage API Data Transfer Optimization" Phase III).

Special notes for your reviewer:

• Cloud-side prerequisite: the API server needs to add per_node_db_url to the response of get_upload_urls_by_session_id (same presigned-URL pattern as cll_map_url, content type application/octet-stream). CLI handles missing key gracefully, so this PR can land independently of that work.
• 7 new tests in tests/test_cli_per_node_db.py:
  • Cloud happy path (PUTs verified)
  • Missing-key graceful degradation
  • Scratch-dir cleanup after success
  • Local-mode non-regression
  • Contract parity vs. DbtAdapter.get_model() on the tests/manifest.json + catalog.json jaffle_shop fixture
  • Mode-switching safety
• One test in tests/test_cli_cache.py retargeted (test_init_cloud_upload_partial_failure_shows_warning) since the cll_cache_url upload branch is now deleted
• Full suite: 1106 passed, 5 pre-existing SPA failures (unchanged from feat: precompute per_node.db in recce init --cloud [DRC-3295] #1334 — test_spa_route_* requires a built frontend that's not in the worktree)
• Review focus: correctness of the cloud / local branch split around cache_db path; try/finally cleanup semantics; contract-test coverage

Does this PR introduce a user-facing change?:

Cloud users (implicit): running recce init --cloud now uploads an extra per_node.db artifact and no longer uploads cll_cache.db. Consumers in Recce Cloud will begin reading per_node.db once the Cloud-side URL key is added. Nothing breaks in the meantime — the cll_cache.db upload path was already only read via the cll_cache_url key, which Cloud will continue to provide transparently during migration (CLI just ignores it).

Local users (no change): local recce init behavior is unchanged.

NONE (user-visible), but the cloud artifact set does change — covered by the cross-repo coordination note above.

[even-wei]

Heads-up — pushing a revert commit shortly.

I had this PR suppress the cll_cache.db upload in cloud mode based on a misread of the design. cll_cache.db is actually load-bearing: it enables cross-session warm-cache reuse for OSS users and cloud sessions alike (downloaded at session init, uploaded at completion, reused by build_full_cll_map to skip already-computed CLL slices).

Incoming fix:

• cache_db default path restored to ~/.recce/cll_cache.db (or --cache-db override)
• cll_cache_upload_url upload block restored
• per_node.db stays tempdir-scoped (it IS genuinely a throwaway per-task artifact)
• Tests updated to assert cll_cache.db IS uploaded in cloud mode

Fix commit inbound. Please hold review until it lands — or review just the per_node.db emission path if it helps.

[even-wei]

Consolidated into #1334 for commit-by-commit review. PR 2's two commits (cb8d74f1 CLI wire-in + eff86d6e cache.db fix) are in #1334 now via fast-forward. GitHub auto-marked this as merged when the source branch was absorbed — that's accurate from its perspective. Deleting the source branch.