feat(kernel-store): support absolute database paths

[grypez]

Modify getDBFilename to detect and pass through absolute paths unchanged, instead of always joining them with the base directory. This enables the daemon to store its database at a fixed location outside the default relative path (e.g. ~/.ocap/kernel.db).

---

Note

Low Risk
Small, well-tested path-handling change limited to database filename resolution; main risk is unexpected directory creation/permission failures for absolute paths.

Overview
Enables configuring SQLite storage using an absolute dbFilename by updating getDBFilename to detect absolute paths, mkdir the parent directory, and return the path unchanged.

Adds a focused unit test to assert the absolute-path behavior (including ensuring the parent directory is created) while preserving existing in-memory (:...) and tmpdir-relative path handling.

^{Written by Cursor Bugbot for commit 0cae785. This will update automatically on new commits. Configure here.}

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	78.24% ⬆️ +0.01%	6169 / 7884
🔵	Statements	78.22% ⬆️ +0.01%	6268 / 8013
🔵	Functions	76.47% 🟰 ±0%	1570 / 2053
🔵	Branches	78.27% ⬆️ +0.01%	2252 / 2877

File Coverage

File	Stmts	Branches	Functions	Lines	Uncovered Lines
Changed Files
packages/kernel-store/src/sqlite/nodejs.ts	98.95% ⬆️ +0.03%	93.33% ⬆️ +0.48%	100% 🟰 ±0%	98.95% ⬆️ +0.03%	82

Generated in workflow #3618 for commit 0cae785 by the Vitest Coverage Report Action