feat: add growth tracking page and related functionality

- Implemented a new Growth page to track practice time and trends.
- Added API integration for fetching review data.
- Created components for displaying practice statistics and trends.
- Updated navigation titles for the main index and growth pages.
- Removed unused styles from the index page.
- Introduced a Projects management page for adding and editing practice projects.
- Developed a Record form for logging practice sessions with validation.
- Added utility functions for date manipulation and duration formatting.
- Implemented error handling and session management in the practice service.
- Created unit tests for the practice service to ensure reliability.

backend/internal/database/001_practice.sql

@@ -0,0 +1,47 @@
+CREATE TABLE users (
+    id text PRIMARY KEY,
+    wechat_identity text NOT NULL UNIQUE,
+    created_at timestamptz NOT NULL DEFAULT now()
+);
+
+CREATE TABLE sessions (
+    token_hash text PRIMARY KEY,
+    user_id text NOT NULL REFERENCES users(id),
+    expires_at timestamptz NOT NULL
+);
+CREATE INDEX sessions_expiry ON sessions(expires_at);
+
+CREATE TABLE projects (
+    id text PRIMARY KEY,
+    user_id text NOT NULL REFERENCES users(id),
+    name text NOT NULL CHECK (char_length(btrim(name)) BETWEEN 1 AND 40),
+    archived boolean NOT NULL DEFAULT false,
+    created_at timestamptz NOT NULL DEFAULT now(),
+    position bigint GENERATED ALWAYS AS IDENTITY,
+    UNIQUE (user_id, id)
+);
+CREATE INDEX projects_owner ON projects(user_id, position);
+
+CREATE TABLE records (
+    id text PRIMARY KEY,
+    user_id text NOT NULL REFERENCES users(id),
+    project_id text NOT NULL,
+    practice_date date NOT NULL CHECK (practice_date >= DATE '0001-01-01'),
+    minutes integer NOT NULL CHECK (minutes > 0),
+    note text NOT NULL DEFAULT '' CHECK (char_length(note) <= 2000),
+    created_at timestamptz NOT NULL DEFAULT now(),
+    updated_at timestamptz NOT NULL DEFAULT now(),
+    FOREIGN KEY (user_id, project_id) REFERENCES projects(user_id, id) ON DELETE RESTRICT
+);
+CREATE INDEX records_owner_date ON records(user_id, practice_date DESC, id DESC);
+CREATE INDEX records_owner_updated ON records(user_id, updated_at DESC, id DESC);
+CREATE INDEX records_project ON records(user_id, project_id);
+
+-- Keep submission receipts after a record is deleted so a delayed retry cannot resurrect it.
+CREATE TABLE submissions (
+    user_id text NOT NULL REFERENCES users(id),
+    request_id text NOT NULL,
+    payload_hash text NOT NULL,
+    record_id text NOT NULL,
+    PRIMARY KEY (user_id, request_id)
+);

backend/internal/database/migrate.go

@@ -0,0 +1,41 @@
+package database
+
+import (
+	"context"
+	_ "embed"
+	"fmt"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+//go:embed 001_practice.sql
+var practiceSQL string
+
+// Migrate applies versioned migrations atomically. A transaction-scoped lock keeps
+// concurrent service starts from applying the same version twice.
+func Migrate(ctx context.Context, pool *pgxpool.Pool) error {
+	tx, err := pool.Begin(ctx)
+	if err != nil {
+		return err
+	}
+	defer tx.Rollback(ctx)
+	if _, err = tx.Exec(ctx, "SELECT pg_advisory_xact_lock(684127930)"); err != nil {
+		return err
+	}
+	if _, err = tx.Exec(ctx, "CREATE TABLE IF NOT EXISTS schema_migrations (version integer PRIMARY KEY, applied_at timestamptz NOT NULL DEFAULT now())"); err != nil {
+		return err
+	}
+	var applied bool
+	if err = tx.QueryRow(ctx, "SELECT EXISTS(SELECT 1 FROM schema_migrations WHERE version=1)").Scan(&applied); err != nil {
+		return err
+	}
+	if !applied {
+		if _, err = tx.Exec(ctx, practiceSQL); err != nil {
+			return fmt.Errorf("migration 1: %w", err)
+		}
+		if _, err = tx.Exec(ctx, "INSERT INTO schema_migrations(version) VALUES (1)"); err != nil {
+			return err
+		}
+	}
+	return tx.Commit(ctx)
+}