feat: Goal Progress Log - backend + API (v2.1)

Implemented progress tracking system for all goals.

**Backend:**
- Migration 030: goal_progress_log table with unique constraint per day
- Trigger: Auto-update goal.current_value from latest progress
- Endpoints: GET/POST/DELETE /api/goals/{id}/progress
- Pydantic Models: GoalProgressCreate, GoalProgressUpdate

**Features:**
- Manual progress tracking for custom goals (flexibility, strength, etc.)
- Full history with date, value, note
- current_value always reflects latest progress entry
- One entry per day per goal (unique constraint)
- Cascade delete when goal is deleted

**API:**
- GET /api/goals/{goal_id}/progress - List all entries
- POST /api/goals/{goal_id}/progress - Log new progress
- DELETE /api/goals/{goal_id}/progress/{progress_id} - Delete entry

**Next:** Frontend UI (progress button, modal, history list)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/migrations/030_goal_progress_log.sql

@@ -0,0 +1,64 @@
+-- Migration 030: Goal Progress Log
+-- Date: 2026-03-27
+-- Purpose: Track progress history for all goals (especially custom goals without data source)
+
+-- ============================================================================
+-- Goal Progress Log Table
+-- ============================================================================
+
+CREATE TABLE IF NOT EXISTS goal_progress_log (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    goal_id UUID NOT NULL REFERENCES goals(id) ON DELETE CASCADE,
+    profile_id UUID NOT NULL REFERENCES profiles(id) ON DELETE CASCADE,
+
+    -- Progress data
+    date DATE NOT NULL,
+    value DECIMAL(10,2) NOT NULL,
+    note TEXT,
+
+    -- Metadata
+    source VARCHAR(20) DEFAULT 'manual' CHECK (source IN ('manual', 'automatic', 'import')),
+    created_at TIMESTAMP DEFAULT NOW(),
+    updated_at TIMESTAMP DEFAULT NOW(),
+
+    -- Constraints
+    CONSTRAINT unique_progress_per_day UNIQUE(goal_id, date)
+);
+
+CREATE INDEX idx_goal_progress_goal_date ON goal_progress_log(goal_id, date DESC);
+CREATE INDEX idx_goal_progress_profile ON goal_progress_log(profile_id);
+
+COMMENT ON TABLE goal_progress_log IS 'Progress history for goals - enables manual tracking for custom goals and charts';
+COMMENT ON COLUMN goal_progress_log.value IS 'Progress value in goal unit (e.g., kg, cm, points)';
+COMMENT ON COLUMN goal_progress_log.source IS 'manual: user entered, automatic: computed from data source, import: CSV/API';
+
+-- ============================================================================
+-- Function: Update goal current_value from latest progress
+-- ============================================================================
+
+CREATE OR REPLACE FUNCTION update_goal_current_value()
+RETURNS TRIGGER AS $$
+BEGIN
+    -- Update current_value in goals table with latest progress entry
+    UPDATE goals
+    SET current_value = (
+        SELECT value
+        FROM goal_progress_log
+        WHERE goal_id = NEW.goal_id
+        ORDER BY date DESC
+        LIMIT 1
+    ),
+    updated_at = NOW()
+    WHERE id = NEW.goal_id;
+
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+-- Trigger: Auto-update current_value when progress is added/updated
+CREATE TRIGGER trigger_update_goal_current_value
+AFTER INSERT OR UPDATE ON goal_progress_log
+FOR EACH ROW
+EXECUTE FUNCTION update_goal_current_value();
+
+COMMENT ON FUNCTION update_goal_current_value IS 'Auto-update goal.current_value when new progress is logged';

backend/routers/goals.py

@@ -77,6 +77,17 @@ class FitnessTestCreate(BaseModel):
     test_date: date
     test_conditions: Optional[str] = None
 
+class GoalProgressCreate(BaseModel):
+    """Log progress for a goal"""
+    date: date
+    value: float
+    note: Optional[str] = None
+
+class GoalProgressUpdate(BaseModel):
+    """Update progress entry"""
+    value: Optional[float] = None
+    note: Optional[str] = None
+
 class GoalTypeCreate(BaseModel):
     """Create custom goal type definition"""
     type_key: str
@@ -511,6 +522,117 @@ def delete_goal(goal_id: str, session: dict = Depends(require_auth)):
 
         return {"message": "Ziel gelöscht"}
 
+# ============================================================================
+# Goal Progress Endpoints
+# ============================================================================
+
+@router.get("/{goal_id}/progress")
+def get_goal_progress(goal_id: str, session: dict = Depends(require_auth)):
+    """Get progress history for a goal"""
+    pid = session['profile_id']
+
+    with get_db() as conn:
+        cur = get_cursor(conn)
+
+        # Verify ownership
+        cur.execute(
+            "SELECT id FROM goals WHERE id = %s AND profile_id = %s",
+            (goal_id, pid)
+        )
+        if not cur.fetchone():
+            raise HTTPException(status_code=404, detail="Ziel nicht gefunden")
+
+        # Get progress entries
+        cur.execute("""
+            SELECT id, date, value, note, source, created_at
+            FROM goal_progress_log
+            WHERE goal_id = %s
+            ORDER BY date DESC
+        """, (goal_id,))
+
+        entries = cur.fetchall()
+        return [r2d(e) for e in entries]
+
+@router.post("/{goal_id}/progress")
+def create_goal_progress(goal_id: str, data: GoalProgressCreate, session: dict = Depends(require_auth)):
+    """Log new progress for a goal"""
+    pid = session['profile_id']
+
+    with get_db() as conn:
+        cur = get_cursor(conn)
+
+        # Verify ownership
+        cur.execute(
+            "SELECT id, unit FROM goals WHERE id = %s AND profile_id = %s",
+            (goal_id, pid)
+        )
+        goal = cur.fetchone()
+        if not goal:
+            raise HTTPException(status_code=404, detail="Ziel nicht gefunden")
+
+        # Insert progress entry
+        try:
+            cur.execute("""
+                INSERT INTO goal_progress_log (goal_id, profile_id, date, value, note, source)
+                VALUES (%s, %s, %s, %s, %s, 'manual')
+                RETURNING id
+            """, (goal_id, pid, data.date, data.value, data.note))
+
+            progress_id = cur.fetchone()['id']
+
+            # Trigger will auto-update goals.current_value
+            return {
+                "id": progress_id,
+                "message": f"Fortschritt erfasst: {data.value} {goal['unit']}"
+            }
+
+        except Exception as e:
+            if "unique_progress_per_day" in str(e):
+                raise HTTPException(
+                    status_code=400,
+                    detail=f"Für {data.date} existiert bereits ein Eintrag. Bitte bearbeite den existierenden Eintrag."
+                )
+            raise HTTPException(status_code=500, detail=f"Fehler beim Speichern: {str(e)}")
+
+@router.delete("/{goal_id}/progress/{progress_id}")
+def delete_goal_progress(goal_id: str, progress_id: str, session: dict = Depends(require_auth)):
+    """Delete progress entry"""
+    pid = session['profile_id']
+
+    with get_db() as conn:
+        cur = get_cursor(conn)
+
+        # Verify ownership
+        cur.execute(
+            "SELECT id FROM goals WHERE id = %s AND profile_id = %s",
+            (goal_id, pid)
+        )
+        if not cur.fetchone():
+            raise HTTPException(status_code=404, detail="Ziel nicht gefunden")
+
+        # Delete progress entry
+        cur.execute(
+            "DELETE FROM goal_progress_log WHERE id = %s AND goal_id = %s AND profile_id = %s",
+            (progress_id, goal_id, pid)
+        )
+
+        if cur.rowcount == 0:
+            raise HTTPException(status_code=404, detail="Progress-Eintrag nicht gefunden")
+
+        # After deletion, recalculate current_value from remaining entries
+        cur.execute("""
+            UPDATE goals
+            SET current_value = (
+                SELECT value FROM goal_progress_log
+                WHERE goal_id = %s
+                ORDER BY date DESC
+                LIMIT 1
+            )
+            WHERE id = %s
+        """, (goal_id, goal_id))
+
+        return {"message": "Progress-Eintrag gelöscht"}
+
 @router.get("/grouped")
 def get_goals_grouped(session: dict = Depends(require_auth)):
     """

frontend/src/utils/api.js

@@ -345,6 +345,11 @@ export const api = {
   updateGoal:             (id,d)  => req(`/goals/${id}`, jput(d)),
   deleteGoal:             (id)    => req(`/goals/${id}`, {method:'DELETE'}),
 
+  // Goal Progress (v2.1)
+  listGoalProgress:       (id)    => req(`/goals/${id}/progress`),
+  createGoalProgress:     (id,d)  => req(`/goals/${id}/progress`, json(d)),
+  deleteGoalProgress:     (gid,pid) => req(`/goals/${gid}/progress/${pid}`, {method:'DELETE'}),
+
   // Goal Type Definitions (Phase 1.5)
   listGoalTypeDefinitions: ()     => req('/goals/goal-types'),
   createGoalType:          (d)    => req('/goals/goal-types', json(d)),