Add explicit collection readiness detection with isReady() and markReady()

[KyleAMathews]

Summary

This PR implements explicit collection readiness detection as requested in #266, replacing the previous approach of using commits as readiness signals.

Changes Made

• Add isReady() method to check if a collection is ready for use
• Add onFirstReady() method to register callbacks for when collection becomes ready (replaces onFirstCommit())
• Add markReady() to SyncConfig interface for sync implementations to explicitly signal readiness
• Update status state machine to allow loading → ready transition for cases with no data to commit
• Update all sync implementations (Electric, Query, Local-only, Local-storage) to use markReady()
• Improve error handling by allowing collections to be marked ready even when sync errors occur

Benefits

• More intuitive API for determining collection readiness
• Better handling of edge cases (empty backends, network errors)
• Eliminates the need for awkward empty commits just to signal readiness
• Maintains full backwards compatibility with existing code

Test Coverage

All tests pass (716 tests), including new lifecycle tests that verify the readiness detection works correctly in various scenarios.

Fixes #266

🤖 Generated with Claude Code

[changeset-bot]

🦋 Changeset detected

Latest commit: 56c0a2e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 6 packages

Name	Type
@tanstack/electric-db-collection	Patch
@tanstack/query-db-collection	Patch
@tanstack/db	Patch
@tanstack/db-example-react-todo	Patch
@tanstack/react-db	Patch
@tanstack/vue-db	Patch

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[pkg-pr-new]

@tanstack/db-example-react-todo

@tanstack/db

npm i https://pkg.pr.new/@tanstack/db@270

@tanstack/electric-db-collection

npm i https://pkg.pr.new/@tanstack/electric-db-collection@270

@tanstack/query-db-collection

npm i https://pkg.pr.new/@tanstack/query-db-collection@270

@tanstack/react-db

npm i https://pkg.pr.new/@tanstack/react-db@270

@tanstack/vue-db

npm i https://pkg.pr.new/@tanstack/vue-db@270

commit: 56c0a2e

[github-actions]

Size Change: +295 B (+0.78%)

Total Size: 38.2 kB

Filename	Size	Change
./packages/db/dist/esm/collection.js	8.71 kB	+256 B (+3.03%)
./packages/db/dist/esm/local-only.js	827 B	+12 B (+1.47%)
./packages/db/dist/esm/local-storage.js	2.09 kB	+16 B (+0.77%)
./packages/db/dist/esm/query/live-query-collection.js	2.07 kB	+11 B (+0.54%)

ℹ️ View Unchanged

Filename	Size
./packages/db/dist/esm/deferred.js	230 B
./packages/db/dist/esm/errors.js	150 B
./packages/db/dist/esm/index.js	568 B
./packages/db/dist/esm/optimistic-action.js	294 B
./packages/db/dist/esm/proxy.js	3.79 kB
./packages/db/dist/esm/query/builder/functions.js	531 B
./packages/db/dist/esm/query/builder/index.js	3.68 kB
./packages/db/dist/esm/query/builder/ref-proxy.js	842 B
./packages/db/dist/esm/query/compiler/evaluators.js	1.34 kB
./packages/db/dist/esm/query/compiler/group-by.js	2.09 kB
./packages/db/dist/esm/query/compiler/index.js	1.75 kB
./packages/db/dist/esm/query/compiler/joins.js	1.2 kB
./packages/db/dist/esm/query/compiler/order-by.js	933 B
./packages/db/dist/esm/query/compiler/select.js	657 B
./packages/db/dist/esm/query/ir.js	318 B
./packages/db/dist/esm/query/optimizer.js	2.24 kB
./packages/db/dist/esm/SortedMap.js	1.24 kB
./packages/db/dist/esm/transactions.js	2.29 kB
./packages/db/dist/esm/utils.js	419 B

_{compressed-size-action::db-package-size}

[github-actions]

Size Change: 0 B

Total Size: 1.05 kB

ℹ️ View Unchanged

Filename	Size
./packages/react-db/dist/esm/index.js	152 B
./packages/react-db/dist/esm/useLiveQuery.js	902 B

_{compressed-size-action::react-db-package-size}

[samwillis]

LGTM