feat(llm-aliases): M5 — migrate consumers to MANA_LLM aliases

Final milestone of docs/plans/llm-fallback-aliases.md. Every backend
caller now requests models via the `mana/<class>` alias system instead
of hardcoded `ollama/...` strings. mana-llm resolves aliases through
`services/mana-llm/aliases.yaml` with health-aware fallback (M3) and
emits resolved-model + fallback metrics (M4).

SSOT moved to `packages/shared-ai/src/llm-aliases.ts` so apps/api,
apps/mana/apps/web, and services/mana-ai all import the same
`MANA_LLM` constant via the existing `@mana/shared-ai` workspace
dependency. Three additional sites (memoro-server, mana-events,
mana-research) inline the alias string with a SSOT comment because
they don't pull @mana/shared-ai today.

Migrated 14 sites across 10 files:
- apps/api: writing(LONG_FORM), comic(STRUCTURED), context(FAST_TEXT),
  food(VISION), plants(VISION), research orchestrator (3 tiers
  collapsed to STRUCTURED+FAST_TEXT/LONG_FORM)
- apps/mana/apps/web: voice/parse-task + parse-habit (STRUCTURED)
- services/mana-ai: planner llm-client + tick.ts (REASONING)
- services/mana-events: website-extractor (STRUCTURED, inlined)
- services/mana-research: mana-llm client (FAST_TEXT, inlined)
- apps/memoro/apps/server: ai.ts (FAST_TEXT, inlined)

Legacy env-vars removed: WRITING_MODEL, COMIC_STORYBOARD_MODEL,
VISION_MODEL, MANA_LLM_DEFAULT_MODEL. The chain in aliases.yaml is
now the single tuning surface; SIGHUP reloads it without redeploys.

New `scripts/validate-llm-strings.mjs` regex-scans 2538 files for
hardcoded `<provider>/<model>` strings and fails the build if any
land outside the SSOT or the explicitly-allowed paths (image-gen
modules, model-inspector code, this validator itself, the registry).
Wired into `validate:all` next to the i18n + theme validators.

Verified: `pnpm validate:llm-strings` clean, `pnpm --filter @mana/api
type-check` clean, `pnpm --filter @mana/ai-service type-check`
clean. Web type-check has 2 pre-existing errors in
SettingsSidebar.svelte (i18n MessageFormatter type drift, last
touched in 988c17a67 — unrelated to this work).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/shared-ai/src/index.ts

@@ -37,6 +37,9 @@ export {
 	isFromMissionRunner,
 } from './actor';
 
+export type { FieldMeta, FieldOrigin } from './field-meta';
+export { makeFieldMeta, isUserOriginatedField } from './field-meta';
+
 export type {
 	IterationPhase,
 	Mission,
@@ -166,3 +169,5 @@ export type {
 	WorkbenchTemplateCategory,
 } from './agents';
 export { DEFAULT_AGENT_ID, DEFAULT_AGENT_NAME, ALL_TEMPLATES, getTemplateById } from './agents';
+
+export { MANA_LLM, type ManaLlmAlias } from './llm-aliases';

packages/shared-ai/src/llm-aliases.ts

@@ -0,0 +1,25 @@
+/**
+ * Mana LLM model aliases — single source of truth for which class of
+ * model each backend feature uses.
+ *
+ * Resolved server-side by mana-llm via `services/mana-llm/aliases.yaml`;
+ * consumers don't see the underlying provider/model unless they really
+ * need to (mainly for token-cost accounting via the
+ * `X-Mana-LLM-Resolved` response header).
+ *
+ * Plan: docs/plans/llm-fallback-aliases.md.
+ */
+export const MANA_LLM = {
+	/** Short answers, classification, single-shot Q&A. Cheap class. */
+	FAST_TEXT: 'mana/fast-text',
+	/** Writing, essays, stories, longer prose. */
+	LONG_FORM: 'mana/long-form',
+	/** JSON output (comic storyboards, research subqueries, voice-intent parsing). */
+	STRUCTURED: 'mana/structured',
+	/** Agent missions, tool calls, multi-step plans. */
+	REASONING: 'mana/reasoning',
+	/** Multimodal (image + text). */
+	VISION: 'mana/vision',
+} as const;
+
+export type ManaLlmAlias = (typeof MANA_LLM)[keyof typeof MANA_LLM];