feat(gitops): config-as-code via .tinyforge.yml for repo-backed workloads

A dockerfile or static workload can opt in to reading its deploy config from a
.tinyforge.yml in its own repo. Tinyforge fetches the file, shows field-level
drift vs the live config, and an admin applies it with an explicit Sync. The
repo becomes the source of truth for the declared fields. Manual-sync only;
no auto-apply on deploy, no multi-workload reconcile, no create/delete in v1.

Scope is deliberately source-aware and source_config-resident: dockerfile
declares port/healthcheck/deploy_strategy, static declares deploy_strategy.
The file never carries repo coords or secrets (those stay in the encrypted
DB), which keeps credentials out of the repo.

Backend:
- internal/gitops: Spec/ParseSpec (KnownFields rejects unknown keys), a
  source-aware ApplyPlan/BuildPlan, MergeAndValidate (omitted-field-preserving
  deep merge + validate-the-merged-result-then-commit — never a partial
  config), declared-only Drift with normalization, and Fetch with
  ok/no_file/fetch_failed/invalid statuses and token-redacted messages.
- staticsite: DownloadFile added to GitProvider + Gitea/GitHub/GitLab impls,
  reusing each provider's SSRF-safe client; 64 KiB cap; ErrFileNotFound.
- store: 4 additive gitops_* columns + setters (disjoint from UpdateWorkload
  so the edit-form save and a sync never clobber each other).
- api: GET /workloads/{id}/gitops (status + raw + live drift + managed_fields),
  PUT /gitops (admin, enable/path, traversal-safe), POST /gitops/sync (admin,
  per-workload locked read->merge->validate->write, audited to event_log).

Frontend:
- GitOpsPanel.svelte: status pill, a purpose-built field-level drift view,
  .tinyforge.yml preview, enable ToggleSwitch, Sync via ConfirmDialog; all five
  statuses handled, admin affordances gated on the real viewer role.
- GitOps-managed badge (list + detail hero) and a read-only edit-form banner.
- api.ts fetchers + types; i18n apps.detail.gitops.* (en + ru parity).

Built phase-by-phase with an adversarial plan review (caught 5 design flaws
pre-implementation) and an independent review per phase (go / security / ts /
final) — all APPROVE, 0 CRITICAL/HIGH. docs/gitops.md documents the schema and
what's intentionally out of v1. Plan: plans/gitops/.

internal/gitops/spec.go

@@ -0,0 +1,57 @@
+// Package gitops implements config-as-code for repo-backed workloads: a
+// dockerfile/static workload can read a small .tinyforge.yml from its own repo
+// that declares a subset of its deploy config. The package is deliberately
+// decoupled from the store and source plugins — it takes a RepoRef (repo
+// coords + a decrypted token) and a live source_config blob, and returns a
+// validated merged config + a field-level drift report. It never writes to the
+// database and never decides to deploy.
+//
+// v1 scope (see plans/gitops/PLAN.md): only source_config-resident fields are
+// overlayable, and the set is source-aware (dockerfile: port/healthcheck/
+// deploy_strategy; static: deploy_strategy). env/faces live in separate stores
+// and are intentionally out of v1; the typed ApplyPlan reserves their slots.
+package gitops
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+
+	"gopkg.in/yaml.v3"
+)
+
+// Spec is the parsed shape of a .tinyforge.yml file (v1).
+type Spec struct {
+	Version int        `yaml:"version"`
+	Deploy  DeploySpec `yaml:"deploy"`
+}
+
+// DeploySpec carries the overlayable deploy fields. Pointers so an omitted key
+// is distinguishable from a zero value — only present (non-nil) fields are
+// applied or drift-compared, so an absent key never clears live config.
+type DeploySpec struct {
+	Port           *int    `yaml:"port"`
+	Healthcheck    *string `yaml:"healthcheck"`
+	DeployStrategy *string `yaml:"deploy_strategy"`
+}
+
+// ParseSpec decodes a .tinyforge.yml body. Unknown keys are rejected
+// (KnownFields) so a typo or an unsupported field — e.g. someone trying to
+// declare env/faces in v1 — surfaces as an error instead of being silently
+// dropped. Only version 1 is accepted.
+func ParseSpec(data []byte) (Spec, error) {
+	var s Spec
+	dec := yaml.NewDecoder(bytes.NewReader(data))
+	dec.KnownFields(true)
+	if err := dec.Decode(&s); err != nil {
+		if errors.Is(err, io.EOF) {
+			return Spec{}, fmt.Errorf("gitops: empty .tinyforge.yml")
+		}
+		return Spec{}, fmt.Errorf("gitops: parse .tinyforge.yml: %w", err)
+	}
+	if s.Version != 1 {
+		return Spec{}, fmt.Errorf("gitops: unsupported version %d (want 1)", s.Version)
+	}
+	return s, nil
+}