Add dev/prod environments with TrueNAS Docker production deploy.

Split PostgreSQL into gallery_dev and gallery_prod, add Docker/Gitea deploy tooling,
SMB image sync, pgAdmin split script, dev:web on Keenetic :5173, and operator docs.

Co-authored-by: Cursor <cursoragent@cursor.com>

db/split-dev-prod.sql

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+-- One-time dev/prod database split on TrueNAS PostgreSQL.
+--
+-- Preferred: pgAdmin on dev PC — open db/split-dev-prod-pgadmin.sql (step-by-step).
+-- Alternative (if psql is installed): psql -h 192.168.10.122 -U postgres -d postgres -f db/split-dev-prod.sql
+--
+-- NOTE: CREATE DATABASE cannot run inside a DO block; this file uses standalone statements.
+
+-- Disconnect clients
+SELECT pg_terminate_backend(pid)
+FROM pg_stat_activity
+WHERE datname IN ('Gallery', 'gallery', 'gallery_prod', 'gallery_dev')
+  AND pid <> pg_backend_pid();
+
+-- Rename legacy → gallery_prod (run ONE of these; comment out the other)
+ALTER DATABASE "Gallery" RENAME TO gallery_prod;
+-- ALTER DATABASE gallery RENAME TO gallery_prod;
+
+-- Disconnect from prod before template clone
+SELECT pg_terminate_backend(pid)
+FROM pg_stat_activity
+WHERE datname = 'gallery_prod' AND pid <> pg_backend_pid();
+
+-- Clone dev from prod (skip if gallery_dev already exists)
+CREATE DATABASE gallery_dev WITH TEMPLATE gallery_prod;
+
+GRANT ALL PRIVILEGES ON DATABASE gallery_dev TO gallery;
+GRANT ALL PRIVILEGES ON DATABASE gallery_prod TO gallery;