chore(deps): typescript 6.0.3 + ignoreDeprecations for baseUrl

[eldonm]

Supersedes #66 (dependabot typescript 5.9.3 → 6.0.3), which failed CI because TS6 promotes the baseUrl deprecation to a hard error:

tsconfig.json(18,5): error TS5101: Option 'baseUrl' is deprecated ... Specify '"ignoreDeprecations": "6.0"' to silence this error.

This branch = the same TS 6.0.3 bump + "ignoreDeprecations": "6.0" in jvchat/tsconfig.json so tsc runs. baseUrl/paths keep resolving; a proper migration off baseUrl (removed in TS7) is follow-up.

Test plan

CI re-runs the jvchat tsc && vite build. If any further TS6 type errors surface behind the (now-cleared) config error, they'll show here.

Closes #66.

🤖 Generated with Claude Code

[eldonm]

Closing — the TS6 code fix works (jvchat builds under TypeScript 6 with "ignoreDeprecations": "6.0" in tsconfig; the jvchat CI job passes). The only blocker is a corrupted jvchat/pnpm-lock.yaml inherited from this branch's stale base — it churned through the dependabot rebases (#67/#68/#69) and now trips check-yaml with duplicate keys that main's lock doesn't have. Hand-deduping a lockfile produces an inconsistent result, so this needs a clean regen rather than a patch.

To redo cleanly:

git checkout main && git pull
git checkout -b chore/typescript-6
# bump typescript to ^6.0.3 in jvchat/package.json
cd jvchat && pnpm install          # regenerates a clean pnpm-lock.yaml
# add "ignoreDeprecations": "6.0" to jvchat/tsconfig.json (baseUrl is a hard error in TS6)
git commit -am "chore(deps): typescript 6 + ignoreDeprecations for baseUrl"

The ignoreDeprecations tsconfig change is the only source edit needed. Low priority (dev tooling). Related: #66 (original dependabot bump, superseded by this).