Plugin framework maturation, reports overhaul, theming, and USB frontend repair

Framework:
- Per-plugin Alembic migration chains (ADR-008): every bundled plugin
  carries its own chain with a stamp-only anchor at the ownership cutover;
  new plugin schema lands in plugins/<name>/migrations/, never the core
  chain. Deploys add flask plugin upgrade-all. Fixed a latent bug in the
  shared alembic template (engine URL resolution) and taught the metadata
  filter to include FK-referenced core tables.
- Frontend plugin route gating (ADR-009): plugin routes carry meta.plugin;
  a disabled plugin's pages redirect to the dashboard via a cached,
  fail-open check against the new public GET /api/plugins/enabled.
- get_reports() plugin hook (contract 0.5.0 -> 0.6.0): plugins contribute
  report cards; warranty and toner cards moved off the hardcoded list.

Reports:
- Hub grouped by category with search; inline reports render at the top,
  are URL-backed (?report=id, back-button and deep links work), expose
  their server-side filter params as controls, and export CSV. Warranty
  and Toner pages gained CSV export.
- Deleted the dead legacy Warranty Status report (always-zero buckets
  from a retired column).

Theming and fonts:
- Inter (variable) bundled locally via @fontsource, replacing the Google
  Fonts Roboto import - air-gapped installs now render correctly; tables
  use tabular numerals.
- Optional brand_primary_dark_color, brand_accent_color,
  brand_sidebar_color settings applied to CSS vars at bootstrap.

USB frontend repair (views were reading a dead legacy shape):
- List/detail/form and the employee profile USB panels remapped to the
  real API shape (device_id/device_desc/checkinoutlog); employee panels
  now use /usb/checkouts endpoints; external-mode /usb/checkouts/active
  honors the badge filter; dead client methods pruned.

Also: warranties list page no longer requires login (matches app
convention); collector doc rewritten with a GE-Enforce integration guide
and paste-ready PowerShell reporter; ADR index and CHANGELOG updated.

Verified: 323 tests pass, naming/style green, frontend builds, plugin
migration dry-run green on scratch MySQL.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/PLUGINS.md

@@ -4,7 +4,7 @@ shopdb-flask is a framework. The plugins listed here are the pieces other GE Aer
 
 ## Bundled (ship with the framework)
 
-These six plugins are in `plugins/` in this repo. Enable per site with `flask plugin install <name>`.
+These plugins are in `plugins/` in this repo. Enable per site with `flask plugin install <name>`.
 
 | Plugin | Tracks | Notes |
 |--------|--------|-------|
@@ -14,16 +14,16 @@ These six plugins are in `plugins/` in this repo. Enable per site with `flask pl
 | `network` | Switches, routers, access points, IDFs as locations | Asset-only; cleanest of the bundled set. |
 | `usb` | USB devices issued to shop-floor users | Lightweight checkout / check-in. |
 | `notifications` | Shop-floor notifications, recognitions, kiosk feed | Used by `ShopfloorDashboard.vue`. |
-
-## Planned (in the roadmap, not yet built)
-
-| Plugin | Tracks | Status |
-|--------|--------|--------|
-| `measuringtools` | Metrology and inspection: CMMs, Keyence vision, surface profilometers, GenSpec | Per [ADR-005](adr/ADR-005-equipment-vs-measuringtools.md). First plugin to be built using `flask plugin new` as the canary for the scaffold. |
+| `measuringtools` | Metrology and inspection instruments: calipers, micrometers, thread/bore/height gages, indicators | Per [ADR-005](adr/ADR-005-equipment-vs-measuringtools.md). Calibration lifecycle with derived status. First plugin built on the matured scaffold; its walkthrough is [PLUGIN-GUIDE.md](PLUGIN-GUIDE.md). Ships `default_enabled: false`. |
 
 ## Building your own
 
-See [PLUGIN-QUICKSTART.md](PLUGIN-QUICKSTART.md) for the 30-minute walkthrough. The contract is locked in [ADR-001](adr/ADR-001-asset-as-platform-contract.md) and versioned per [ADR-002](adr/ADR-002-plugin-versioning.md).
+Two guides:
+
+- [PLUGIN-QUICKSTART.md](PLUGIN-QUICKSTART.md) - generate, customize, install, and test a plugin in 30 minutes using `flask plugin new`.
+- [PLUGIN-GUIDE.md](PLUGIN-GUIDE.md) - the full narrative walkthrough of building the `measuringtools` plugin, the exemplar that exercises every current framework feature (models, per-plugin migrations, authz, hooks, frontend integration, tests).
+
+The contract is locked in [ADR-001](adr/ADR-001-asset-as-platform-contract.md) and versioned per [ADR-002](adr/ADR-002-plugin-versioning.md).
 
 Quick path:
 
@@ -33,6 +33,29 @@ flask plugin new cameras --description "Tracks shop-floor surveillance cameras"
 flask plugin install cameras
 ```
 
+## Migrations (per-plugin chains)
+
+Each plugin that owns tables carries its own Alembic chain under
+`plugins/<name>/migrations/`, with a per-plugin version table
+`alembic_version_<name>` independent of the core `alembic_version`. Ownership is
+split at a fixed cutover (see [ADR-008](adr/ADR-008-plugin-migration-ownership.md)):
+
+- The core chain (`flask db upgrade`) created every table that existed through
+  its head, including the bundled-plugin tables. Each bundled plugin's `0001`
+  migration is a stamp-only no-op anchor recording that fact.
+- From the cutover forward, a change to a plugin's schema lands as
+  `plugins/<name>/migrations/versions/000N_*.py`, never in the core chain. The
+  core chain is reserved for core tables.
+- A plugin built AFTER the cutover (e.g. `measuringtools`) is different: the
+  core chain never created its tables, so its `0001` is a REAL baseline that
+  creates them, not a no-op anchor. See [PLUGIN-GUIDE.md](PLUGIN-GUIDE.md) for
+  the anchor-vs-baseline distinction.
+
+Deploys and upgrades run `flask db upgrade` then `flask plugin upgrade-all`.
+`upgrade-all` stamps every plugin anchor and applies any later plugin
+migrations; it is idempotent. The registry (`instance/plugins.json`) records
+which revisions each plugin has applied in `migrations_applied`.
+
 ## Distribution conventions
 
 For sister-site plugins (per [ADR-003](adr/ADR-003-plugin-distribution.md)):