npm 12: global install blocks better-sqlite3 and postinstall scripts, leaving tt broken on first run

[mostlydev]

Problem

npm 12 no longer runs dependency install scripts by default. Codex verified this in a fresh global prefix during the 0.15.0 release:

• npm install -g talking-stick (0.15.0 tarball) exits 0, but blocks the install scripts of both talking-stick (postinstall: skiller bootstrap / skill sync) and better-sqlite3 (native binding build).
• The first tt command that touches room state fails with better-sqlite3's "Could not locate the bindings file".

This isn't a 0.15.0 regression: 0.14.x has the same dependency and would behave the same on npm 12. Approving the scripts, or rebuilding better-sqlite3, fixes the install.

Suggested fixes

1. Docs, now: document the npm 12 install step in README Quickstart, i.e. whatever allow-scripts approval npm 12 expects for talking-stick and better-sqlite3, or a follow-up npm rebuild -g better-sqlite3.
2. Clear runtime error: catch the missing-binding error when opening the DB and print an actionable message with the exact command, instead of the raw bindings stack.
3. Longer term: evaluate node:sqlite (built into Node ≥22.5) to drop the native dependency entirely, which would also make installs script-free. The postinstall skill sync already has a fallback on the first human CLI run.

Environment

npm 12.0.2, Node 22/24, macOS. Found during the 0.15.0 release (PR #70).