refactor: rename MESH_* env vars to STUDIO_* with fallback

[viktormarinho]

De-mesh migration task 06: env vars. All MESH_* environment variables are renamed to STUDIO_*. Reads go through central points that prefer the new name and fall back to the legacy one with a one-time deprecation warning (envWithFallback in apps/mesh/src/settings/env-fallback.ts), so existing deploys keep working unchanged.

Renames

Old	New	Fallback?
MESH_JWT_SECRET	STUDIO_JWT_SECRET	yes (resolve-config, warns once)
MESH_DISPATCH_ROLE	STUDIO_DISPATCH_ROLE	yes (resolve-config, warns once)
MESH_PUBLIC_URL	STUDIO_PUBLIC_URL	yes (getPublicUrl, warns once)
MESH_CLUSTER_URL	STUDIO_CLUSTER_URL	yes (deco link, warns once); dev-spawned link daemon + resilience compose now emit the new name
MESH_TEST_SESSION / MESH_BASE_URL (smoke script)	STUDIO_TEST_SESSION / STUDIO_BASE_URL	yes (silent ??, dev-only script)
MESH_API_KEY / MESH_BASE_URL / MESH_ORG / MESH_AGENT_ID (UI-generated .env snippets)	STUDIO_* equivalents	consumer (@decocms/typegen) already reads STUDIO_* first with MESH_* fallback; docs already use STUDIO_*
env.MESH_REQUEST_CONTEXT (runtime SDK)	env.STUDIO_REQUEST_CONTEXT	yes — withBindings sets both keys to the same object; internal reads prefer new then old; old key kept on DefaultEnv as @deprecated so existing apps compile and run
settings.meshJwtSecret	settings.studioJwtSecret	clean rename — in-memory only, resolved from env at boot, never persisted

Docs (architecture.mdx en/pt, architecture model, runtime/mesh-sdk READMEs) updated to the STUDIO_* names.

Left for task 09 (would break running clusters)

• Helm chart still sets MESH_DISPATCH_ROLE (deploy/helm/studio/templates/*.yaml, _helpers.tpl reserved-name checks, chart README). The chart is an external contract: an upgraded chart setting STUDIO_DISPATCH_ROLE against an older app image (no fallback) would silently coerce every pod to role all, breaking the api/worker split. New app images read both names, so the chart can flip safely in task 09.
• Runtime SDK legacy env keys nothing in this repo reads (MESH_URL, MESH_RUNTIME_TOKEN, MESH_APP_NAME, MESH_APP_DEPLOYMENT_ID on DefaultEnv) are set by external hosts — renaming them is an SDK-major concern, out of scope here.
• Non-env MESH/mesh identifiers (MCP_MESH_KEY metadata key, MESH_PUBLIC_ tool prefix, __MESH_VERSION__ build constant, mesh-storage:// URIs, x-mesh-token) belong to other de-mesh tasks (refactor: rename mesh* internal identifiers to studio* #4619, refactor(auth): rename mesh token symbols to studio with back-compat #4622, refactor(storage): rename mesh-storage URIs to studio-storage with back-compat #4627) and are untouched.

Breaking changes

None. Every rename either has a runtime fallback on the read side or only changes emitted examples/snippets whose documented consumers already accept both names.

Testing

• New unit tests: env-fallback.test.ts (precedence, empty-string, unset), resolve-config.test.ts (STUDIO/MESH precedence + fallback for JWT secret and dispatch role), triggers.test.ts (STUDIO_REQUEST_CONTEXT read; existing tests keep covering the MESH_REQUEST_CONTEXT fallback).
• bun test apps/mesh/src/settings packages/runtime — 107 pass, 0 fail.
• bun run check — all workspaces pass. bun run lint — 30 warnings, identical to main baseline. bun run fmt clean.

🤖 Generated with Claude Code

---

Summary by cubic

Renamed all MESH_* env vars to STUDIO_* with centralized fallback and one-time deprecation warnings. Updated the runtime SDK, CLI, docs, and UI snippets to prefer STUDIO_* without breaking existing deploys.

• Refactors

  • Added envWithFallback to prefer STUDIO_* and fall back to MESH_* with a single warn.
  • Switched reads to STUDIO_JWT_SECRET, STUDIO_DISPATCH_ROLE, STUDIO_PUBLIC_URL, and STUDIO_CLUSTER_URL; kept MESH_* fallback where relevant.
  • Runtime now sets env.STUDIO_REQUEST_CONTEXT alongside the deprecated MESH_REQUEST_CONTEXT and reads new-then-old across helpers/tools/triggers.
  • Updated docs/READMEs and .env snippets to STUDIO_*; added tests for fallback and precedence.

• Migration

  • No breaking changes; legacy MESH_* still work with a deprecation warning. Rename to STUDIO_* when convenient.
  • Helm chart remains on MESH_DISPATCH_ROLE for now; change will happen in a later task to avoid breaking older images.
  • For runtime apps, use env.STUDIO_REQUEST_CONTEXT; MESH_REQUEST_CONTEXT is kept as a deprecated alias.

^{Written for commit f2ba73b. Summary will update on new commits.}