…3664)

## Summary

Companion to #3536, which patched routes that already had a leaking
`catch (e) { return json({error: e.message}, 500) }`. That pattern can't
reach routes which have no catch in the first place — when those throw,
Remix's default error path serializes `error.message` into the response
body, and the SDK then wraps the leaked string as `TriggerApiError`.

Across 28 raw api.v1 loaders/actions plus one dashboard polling
endpoint, each handler now:

- Wraps its body in `try { ... } catch (error) { ... }`.
- Re-throws `Response` instances so auth helpers' `throw json(...)` /
`throw redirect(...)` pass through unchanged.
- Logs non-Response errors via `logger.error` so server-side visibility
is preserved.
- Returns a generic body — `{"error": "Internal Server Error"}` 500 for
raw API routes, or `{ changelogs: [] }` 200 for the polling widget
(degrade silently across transient blips; the consumer hook already
coped with empty payloads).

For six routes where #3536 left an inner try/catch covering only a
service call (`alertChannels`, `batches.results`,
`deployments.finalize`, `deployments.background-workers`,
`deployments.promote`, `projects.background-workers`): an outer
try/catch is added so auth/parsing failures are also sanitized. Inner
typed-error handling (`ServiceValidationError` → 422 with message, etc.)
is preserved exactly.

For two routes whose existing catch returned 400 + `error.message`
(`api.v1.authorization-code`, `api.v1.orgs.\$orgParam.projects` action):
the body is sanitized to a generic per-route string. **Status code stays
400** — clients that key on the 4xx/5xx distinction (and the SDK's
no-retry-on-4xx behavior) are unaffected.

## Test plan

- [x] \`pnpm run typecheck --filter webapp\`
- [x] Per-route synthetic-throw probe: inject \`throw new
Error("SYNTHETIC ...")\` at the top of each catch'd try, curl the route
with a dummy bearer, confirm the response body is the generic shape and
that the synthetic message lands server-side via \`logger.error\`. 29
routes verified.
- [x] Real-P1001 probe on the envvars loader: \`docker stop database\`
mid-flight, confirm response is generic 500 (not the leaked Prisma
message).
- [x] Sampled legitimate 4xx/2xx paths across each pattern variant
(naked-wrap, partial-expanded, 400-preserved) to confirm the wraps don't
interfere with normal control flow.