Dev (#73)

* feat: add provider/model formatting and robust model display parsing ✨

**✨ Features**
- Add formatProviderName and formatModelName helpers to modelCapabilities to produce human-friendly provider and model labels.
- Add extractBackendNameFromTooltip in modelPicker to robustly parse backend names from tooltips with vendor fallback.

**🛠️ Refactor**
- Update LiteLLMProviderBase to use the new formatting helpers, construct stable display IDs and unified tooltips, and simplify item details for consistent UI labels.

**🧪 Tests**
- Update model display test expectations and add tests for formatProviderName/formatModelName; also adjust integration test type declarations for consistency.

**🧹 Chores**
- Bump package.json version to 1.6.1-dev1.
- Change post-session-validation script to run "npm run format" and "npm run lint" instead of the `:check` variants.

**📚 Docs**
- Update project-planner prompt to save plans under `.plans/pending` and remove obsolete deliverables text from plan-generation instructions.

* refactor: standardize model display labels and metadata ✨

**✨ Features**
- Add ExtendedModelInformation type and formatModelDisplayLabel helper to centralize model UI labeling and vendor display.
- Update LiteLLMProviderBase to expose rawModelName, vendor, backendName, tooltip and detail so consumers render consistent model info.
- Normalize provider handling and token fields by using providerLower for family derivation and derived.maxInputTokens for maxInputTokens.

**🐛 Fixes**
- Update post-session validation message to recommend running "npm run format" and "npm run lint" (remove :check variants) so commands match current scripts.

**🧹 Chores**
- Bump package.json version to 1.6.1-dev5.

**🧪 Tests**
- Adjust unit tests to validate new display label formatting and backendName/description values.

* chore: release 1.6.1 — update changelog, bump version, deps & dependabot 🚀

**✨ Features**
- Add 1.6.1 changelog entry documenting model display labels, provider metadata, and token normalization.

**🐛 Fixes**
- Document post-session guidance to run `npm run format` and `npm run lint` in the changelog.

**🧹 Chores**
- Bump package.json version to 1.6.1 to mark the release.
- Update PostHog dependencies (`posthog-js` and `posthog-node`) to newer patch versions.
- Tighten Dependabot: switch npm and GitHub Actions updates to weekly and reduce open PR limit to 5.