Add JtxCollectionProvider and JtxCollection

[sunkup]

Add JtxCollectionProvider + tests and basic JtxCollection as needed for CRUD operations of JtxCollectionProvider.

[Copilot]

Pull request overview

Adds a dedicated JtxCollectionProvider API (plus a lightweight JtxCollection model) to perform CRUD and sync-state operations against the jtx Board content provider, along with instrumentation tests validating the provider behavior.

Changes:

• Introduces JtxCollectionProvider with create/query/update/delete and sync-state helpers for jtx collections.
• Adds JtxCollection wrapper class to represent a single jtx collection and provide convenience update/delete shortcuts.
• Adds JtxCollectionProviderTest instrumentation tests covering CRUD and sync-state read/write.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
lib/src/main/kotlin/at/bitfire/synctools/storage/jtx/JtxCollectionProvider.kt	New provider wrapper around jtx Board collection CRUD + sync-state access.
lib/src/main/kotlin/at/bitfire/synctools/storage/jtx/JtxCollection.kt	New collection model exposing key fields and update/delete shortcuts.
lib/src/androidTest/kotlin/at/bitfire/synctools/storage/jtx/JtxCollectionProviderTest.kt	Instrumentation tests for provider CRUD and sync-state behavior.

Comments suppressed due to low confidence (1)

lib/src/main/kotlin/at/bitfire/synctools/storage/jtx/JtxCollection.kt:68

• issue (blocking): Boolean fields may be parsed incorrectly when provider stores them as "1"/"0" strings.

Same as above for supportsVJournal and readonly: getAsBoolean() will not treat the string "1" as true. Use a conversion that accepts both numeric (0/1) and textual (true/false) representations to match existing jtx handling in the codebase.

    /** see [JtxContract.JtxCollection.SUPPORTSVJOURNAL] */
    val supportsVJournal: Boolean
        get() = values.getAsBoolean(JtxContract.JtxCollection.SUPPORTSVJOURNAL) ?: false

    /** see [JtxContract.JtxCollection.SYNC_ID] */
    val syncId: Long?
        get() = values.getAsLong(JtxContract.JtxCollection.SYNC_ID)

    /** see [JtxContract.JtxCollection.READONLY] */
    val readonly: Boolean
        get() = values.getAsBoolean(JtxContract.JtxCollection.READONLY) ?: false

[cketti]

LGTM 👍