test: push coverage to 90%+ on lines for all files except execute.ts (FAR-85)

Overall before: 80.36% lines / 79.06% statements
Overall after:  94.65% lines / 93.30% statements

Per-file lines coverage (all targets ≥90% except execute.ts):

| File              | Before | After  |
|-------------------|--------|--------|
| ui-parser.ts      | 93.63% | 99.09% |
| cli/format-event  | 59.85% | 99.27% |
| server/execute    | 81.47% | 89.64% |
| server/job-mfst   | 90.30% | 98.78% |
| server/k8s-client | 37.50% | 95.83% |
| server/log-dedup  | 97.77% | 97.77% |
| server/parse      | 89.85% | 98.55% |
| server/skills     | 100%   | 100%   |

New tests added:

- k8s-client.test.ts: getSelfPodInfo (env-var inheritance, secret volumes,
  PVC discovery, dnsConfig, all error paths) + kubeconfig file branch
- format-event.test.ts: parseStdoutLine (cli) — full event-type matrix,
  tool_use status branches, errorText fallback paths
- ui-parser.test.ts: errorText edge cases, empty event paths
- parse.test.ts: errorText fallback to data.message, name, code, JSON
- job-manifest.test.ts: workspace context env wiring, linkedIssueIds,
  paperclipWorkspaces/RuntimeServices JSON, authToken, inherited URLs,
  prompt-secret + data PVC + secret-volume mount paths
- execute.test.ts: parseModelProvider, completionWithGrace,
  instructionsFilePath read failure, ensureAgentDbPvc throw paths,
  large-prompt secret create failure, step-limit detection,
  waitForPod no-pod messaging, init-container ImagePullBackOff /
  CrashLoopBackOff, main-container CrashLoopBackOff, all-inits-done
  happy path, skill bundle source loading (SKILL.md + flat-file
  fallback), SIGTERM handler full body via vi.resetModules()

execute.ts remains at 89.64% lines — the residual gap is deep async/timer
paths inside streamAndAwaitJob (grace poller, keepalive ticker, log-stream
stop-signal/bail timer). Those need fake-timer scaffolding heavier than
this batch warrants; tracking separately.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

src/server/execute.ts

@@ -37,7 +37,7 @@ export function isK8s404(err: unknown): boolean {
   return false;
 }
 
-function parseModelProvider(model: string | null): string | null {
+export function parseModelProvider(model: string | null): string | null {
   if (!model) return null;
   const trimmed = model.trim();
   if (!trimmed.includes("/")) return null;