fix(observability): custom resource attributes use the t3code prefix#23974

Problem

• Unprefixed custom resource attributes (service.component, service.mode, t3.client.surface) sit in namespaces the semantic conventions own, so a future convention key can collide with them, and t3. is not the prefix the rest of T3 Code telemetry uses.

Change

• Attributes specific to T3 Code use the t3code. prefix: t3code.component, t3code.client.surface (now desktop or web for the UI), and t3code.server.managed_by (desktop or standalone).
• Heads up: this renames service.component, t3.client.surface and service.mode, so a query or dashboard that filters on them needs updating.

Scope and approval

• Small, focused rename of attributes T3 Code already exports. No new signal or setting.

Verification

• The new serverLogger.test.ts case (exported resource carries t3code.server.managed_by, process.runtime.name, service.instance.id) passes (7 of 7) and fails with the config change reverted. Format, lint, knip and typecheck pass for the changed scope.
• vp run check:changed with GIT_CONFIG_GLOBAL=/dev/null GIT_CONFIG_SYSTEM=/dev/null: format, lint, knip and typecheck pass; 1761 tests pass and 2 fail in files this change does not touch (ForgejoSourceControlProvider.test.ts "reads Forgejo jobs that did not run as finished checks" and storageCleanup.test.ts "compares the checked-out branch without a full status"). I did not check those two against a clean upstream/main.