Add roaster (machine) management, mobile header-tools redesign, and profile pictures

Machines:
- roasters table + actual_roasts.roaster_id (migrations 009): per-user
  machines with a default; uploads attach to the default roaster and are
  reassignable from the roast detail view
- Learning is now per machine: /api/roaster-profile scopes to a roaster
  (default when unspecified) and applies the user's override tweaks
  (milestone temps, TP time, pace factor) on top of learned medians
- /roasters page: machine list + analysis report showing learned vs
  applied values with editable tweaks, typical RoR, and a plain-language
  list of the adjustments applied to plans; planner honors a manual pace
  override; evaluations use the roast's own machine profile

Mobile header redesign:
- The planner's header tools collapse behind a single 'Tools ▾'
  disclosure (dropdown card) at ≤720px, keeping the fixed three-row
  mobile header with no wrapped or scrolling button rows; desktop
  renders inline via display:contents (same DOM, same handlers)

Profile pictures:
- users.avatar (migration 010) + PUT/GET/DELETE /api/account/avatar;
  client-side centre-crop resize to 128px JPEG; avatar shows in the nav
  chip on every page; included in full backups

Co-Authored-By: Claude Fable 5 <[email protected]>

db/migrations/009_roasters.sql

@@ -0,0 +1,17 @@
+-- Additive only. Per-user roasting machines: uploaded .alogs attach to one, learning is
+-- computed per roaster, and `overrides` stores the user's manual tweaks to what the learned
+-- profile would otherwise apply to their plans (milestone temps, TP time, pace factor).
+CREATE TABLE roasters (
+  id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+  user_id uuid NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+  name text NOT NULL,
+  model text NOT NULL DEFAULT '',
+  notes text NOT NULL DEFAULT '',
+  is_default boolean NOT NULL DEFAULT false,
+  overrides jsonb NOT NULL DEFAULT '{}',
+  created_at timestamptz NOT NULL DEFAULT now(),
+  updated_at timestamptz NOT NULL DEFAULT now()
+);
+CREATE INDEX roasters_user ON roasters(user_id, created_at);
+ALTER TABLE actual_roasts ADD COLUMN roaster_id uuid REFERENCES roasters(id) ON DELETE SET NULL;
+CREATE INDEX actual_roasts_roaster ON actual_roasts(roaster_id);

db/migrations/010_user_avatar.sql

@@ -0,0 +1,2 @@
+-- Additive only. Account profile picture, stored as a small client-side-resized data URL.
+ALTER TABLE users ADD COLUMN avatar text;