Fix WAL mode set and sqlite connection pool setup for cursorcli

[bago2k4]

This pull request improves how SQLite databases are accessed and managed in the Cursor CLI provider, with a focus on connection pooling and ensuring reliable use of WAL (Write-Ahead Logging) mode. The changes prevent file descriptor leaks, ensure consistent file modification detection, and centralize the logic for enabling WAL mode.

Database connection management improvements:

• Limited SQLite connection pools to a single open and idle connection, and set a connection max lifetime to prevent file descriptor accumulation in both sqlite_reader.go and watcher.go. [1] [2] [3] [4]

WAL mode handling enhancements:

• Removed per-connection enabling of WAL mode, and instead introduced a new EnsureWALMode function in sqlite_reader.go that ensures the database is in WAL mode by opening a brief read-write connection. This function is now called once per session when a session is first seen in the watcher. [1] [2] [3]

These changes make database access safer and more reliable, especially under heavy usage or when monitoring many sessions.

[Copilot]

Pull request overview

This PR adjusts how the Cursor CLI provider opens SQLite databases to (1) reduce the chance of accumulating file descriptors via database/sql connection pooling, and (2) centralize enabling SQLite WAL mode into a one-time helper invoked when a session is first detected.

Changes:

• Constrain SQLite connection pools to 1 open / 1 idle connection and set a max lifetime for read-only DB handles used by the watcher and session reader.
• Remove per-read PRAGMA journal_mode=WAL calls and introduce EnsureWALMode(dbPath) to set/verify WAL mode via a brief read-write connection.
• Call EnsureWALMode once when a session is first observed by the watcher.

3 most important improvements to make:

1. Update EnsureWALMode to open SQLite using a safer/consistent DSN (e.g., file: + filepath.ToSlash(...)) and mode=rw to avoid accidentally creating new DB files and to align with the repo’s established SQLite DSN pattern (see specstory-cli/pkg/provenance/store.go:29).
2. Narrow the CursorWatcher mutex scope in hasSessionChanged so the lock only protects map state, not the DB I/O and WAL initialization work.
3. Add a focused unit test for EnsureWALMode (this package already has tests) that creates a temp SQLite DB, checks PRAGMA journal_mode, runs EnsureWALMode, and asserts the mode becomes WAL.

Unit test opportunities (high-signal only):

• A single test covering EnsureWALMode’s journal-mode transition and error behavior (especially if switching to mode=rw) would meaningfully reduce risk without adding tautological coverage.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 6 comments.

File	Description
specstory-cli/pkg/providers/cursorcli/watcher.go	Uses a controlled read-only pool for polling counts and ensures WAL once when a session is first seen.
specstory-cli/pkg/providers/cursorcli/sqlite_reader.go	Applies controlled pooling for reads and adds centralized WAL-mode enforcement via EnsureWALMode.