feat(studio): Flows + Module sheet + System-AI editor i18n (v0.28.0)

- Localize Flows page: app-bar title and reload tooltip,
  hub-unreachable / no-saved-flows empty states, run-flow input
  dialog (title with flow name, description, hint, Cancel /
  Run), running dialog (title, "Flow running…" status, no-output
  message, Close button), flow-card Run button.
- Localize the module-sheet bottom sheet: failed-to-load text,
  Capabilities and "Declared permissions" section headers,
  no-permissions placeholder copy.
- Localize the System-AI configuration dialog: title, intro
  paragraph, provider dropdown label, endpoint label, API-key
  env-var label (required vs optional) and disclaimer, privacy
  mode header and three options (Off / Redacted / Full) plus
  their descriptions, test-result panel ("Connection ok" /
  "Connection failed", "Reply: …" prefix), model picker (label,
  hint fallback, helper text with Ollama variant, Refresh /
  Pull / Pulling… buttons, list errors and empty states),
  hardware banner ("Detected: …" + " · curation reviewed …"
  suffix), suitability legend (recommended / balanced / small /
  large / huge / unknown), cache row with pluralized count and
  Clear button, cache cleared / clear-failed toasts, pull-empty
  / pull-failed errors. Suitability label moved off a getter
  onto a `labelFor(BuildContext)` method so it can read the
  current locale.

Provider preset descriptions and modelHint strings stay in
English in `_ProviderPreset.all` — they're tightly coupled to
the wire-protocol identifiers and would require a runtime
factory rebuild rather than a const list.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/l10n/app_en.arb

@@ -264,6 +264,25 @@
   "modulesUninstallFailed": "Uninstall failed: {error}",
   "@modulesUninstallFailed": { "placeholders": { "error": { "type": "String" } } },
   "modulesUninstalling": "Uninstalling…",
+  "moduleSheetFailedToLoad": "Failed to load: {error}",
+  "@moduleSheetFailedToLoad": { "placeholders": { "error": { "type": "String" } } },
+  "moduleSheetCapabilities": "Capabilities",
+  "moduleSheetPermissions": "Declared permissions",
+  "moduleSheetNoPermissions": "(none — pure-computation module)",
+
+  "flowsTitle": "Flows",
+  "flowsReloadTooltip": "Reload",
+  "flowsNoneTitle": "No saved flows",
+  "flowsNoneHint": "Save a flow with `fai admin flows save <name> <flow.yaml>` and it shows up here.",
+  "flowsRunDialogTitle": "Run {name}",
+  "@flowsRunDialogTitle": { "placeholders": { "name": { "type": "String" } } },
+  "flowsRunDialogBody": "Inputs as key=value, one per line. All values are sent as text payloads. For binary inputs use the `fai run` CLI.",
+  "flowsInputsHint": "name=World\ntarget_language=English\nsummary_style=three bullet points",
+  "flowsRunButton": "Run",
+  "flowsRunningTitle": "Running {name}",
+  "@flowsRunningTitle": { "placeholders": { "name": { "type": "String" } } },
+  "flowsRunning": "Flow running…",
+  "flowsNoOutputs": "Flow completed with no declared outputs.",
 
   "approvalsTitle": "Approvals",
   "approvalsTabPending": "Pending",
@@ -412,5 +431,65 @@
   "@searchStoreHintWithTagline": { "placeholders": { "tagline": { "type": "String" } } },
   "searchStoreHintWithCategory": "store · {category}",
   "@searchStoreHintWithCategory": { "placeholders": { "category": { "type": "String" } } },
-  "searchSavedFlowHint": "saved flow"
+  "searchSavedFlowHint": "saved flow",
+
+  "systemAiTitle": "System AI",
+  "systemAiIntro": "The hub-internal LLM the platform itself uses for inline failure explanations and operator help. Off by default; configure here. See docs/architecture/system-ai.md for what crosses the wire.",
+  "systemAiProviderLabel": "Provider",
+  "systemAiEndpointLabel": "Endpoint URL (up to /v1)",
+  "systemAiApiKeyRequired": "API key env var (required)",
+  "systemAiApiKeyOptional": "API key env var (optional)",
+  "systemAiApiKeyDisclaimer": "Studio never reads or stores the key value — only its env-var name. The hub reads `${name}` at request time.",
+  "@systemAiApiKeyDisclaimer": { "placeholders": { "name": { "type": "String" } } },
+  "systemAiTestConnection": "Test connection",
+  "systemAiTesting": "Testing…",
+  "systemAiSave": "Save",
+  "systemAiPrivacyHeader": "PRIVACY MODE",
+  "systemAiPrivacyOffLabel": "Off",
+  "systemAiPrivacyOffDesc": "Feature disabled. No requests leave the hub.",
+  "systemAiPrivacyRedactedLabel": "Redacted",
+  "systemAiPrivacyRedactedDesc": "Only event_type / error / module names. KRITIS-friendly default.",
+  "systemAiPrivacyFullLabel": "Full",
+  "systemAiPrivacyFullDesc": "Includes the audit detail JSON (hash-only — no raw payloads).",
+  "systemAiConnectionOk": "Connection ok",
+  "systemAiConnectionFailed": "Connection failed",
+  "systemAiReplyPrefix": "Reply: {text}",
+  "@systemAiReplyPrefix": { "placeholders": { "text": { "type": "String" } } },
+  "systemAiModelLabel": "Model (required)",
+  "systemAiModelHintFallback": "model identifier the provider expects",
+  "systemAiModelHelperBase": "Required: pick from the list (Refresh) or type one.",
+  "systemAiModelHelperOllama": "Required: pick from the list (Refresh) or type one. Use Pull to download from Ollama.",
+  "systemAiRefresh": "Refresh",
+  "systemAiPull": "Pull",
+  "systemAiPulling": "Pulling…",
+  "systemAiCouldNotListModels": "Could not list models: {error}",
+  "@systemAiCouldNotListModels": { "placeholders": { "error": { "type": "String" } } },
+  "systemAiNoModelsOllama": "No models on the Ollama server yet. Type one above and click Pull.",
+  "systemAiNoModelsGeneric": "Provider returned no models.",
+  "systemAiSuitabilityRecommended": "recommended",
+  "systemAiSuitabilityBalanced": "balanced",
+  "systemAiSuitabilitySmall": "small — quality may be limited",
+  "systemAiSuitabilityLarge": "large — slower",
+  "systemAiSuitabilityHuge": "huge — likely too slow on a laptop",
+  "systemAiSuitabilityUnknown": "size unknown",
+  "systemAiHwDetected": "Detected: {summary}",
+  "@systemAiHwDetected": { "placeholders": { "summary": { "type": "String" } } },
+  "systemAiHwReviewed": " · curation reviewed {date}",
+  "@systemAiHwReviewed": { "placeholders": { "date": { "type": "String" } } },
+  "systemAiLegendRecommended": "recommended for this hardware{tier}",
+  "@systemAiLegendRecommended": { "placeholders": { "tier": { "type": "String" } } },
+  "systemAiLegendBalanced": "balanced (4-8B)",
+  "systemAiLegendSmallLarge": "small <3B / large 9-15B / above hardware",
+  "systemAiLegendHuge": "huge >15B",
+  "systemAiLegendUnknown": "size unknown",
+  "systemAiCacheRow": "Cache: {n} cached {n, plural, =1{explanation} other{explanations}}. Identical prompts hit the cache; switching model or privacy mode flushes automatically.",
+  "@systemAiCacheRow": { "placeholders": { "n": { "type": "int" } } },
+  "systemAiCacheClear": "Clear",
+  "systemAiCacheClearedToast": "Cleared {n} cached System-AI explanations.",
+  "@systemAiCacheClearedToast": { "placeholders": { "n": { "type": "int" } } },
+  "systemAiCacheClearFailed": "Cache clear failed: {error}",
+  "@systemAiCacheClearFailed": { "placeholders": { "error": { "type": "String" } } },
+  "systemAiPullEmptyError": "Type a model id (e.g. gemma3:4b) first.",
+  "systemAiPullFailedError": "Pull failed: {error}",
+  "@systemAiPullFailedError": { "placeholders": { "error": { "type": "String" } } }
 }