Enhance RxResume validation, settings handling, and caching (#287)

* feat: enhance validation handling in ReactiveResumeConfigPanel and rxresume-config

* feat: enhance RxResume validation handling in SettingsPage and ReactiveResumeSection

* feat: enhance RxResume settings handling and cache management

* feat: add save-time validation and caching for Reactive Resume settings

* refactor: improve code formatting and readability across multiple files

* fix: improve condition check in hasOverrideKey function

* feat: enhance RxResume validation and settings handling with precheck options

* refactor: streamline RxResume client initialization and improve backup sorting logic

docs-site/docs/features/reactive-resume.md

@@ -108,6 +108,14 @@ Or via environment variables:
 
 If you leave the URL blank in the dashboard, JobOps uses `RXRESUME_URL` when it is set; if not set, it falls back to the public cloud default for the selected mode.
 
+### Save-time validation
+
+When you save Reactive Resume credentials or the shared URL in Settings:
+
+1. JobOps validates only the credential-bearing Reactive Resume fields for the selected mode.
+2. Invalid credentials or other `4xx` configuration failures block the save and show a persistent inline error.
+3. Temporary network failures, timeouts, or upstream `5xx` errors show a persistent inline warning, but the save still succeeds.
+
 ### 2) Select base resume
 
 In **Settings → Reactive Resume**:
@@ -139,6 +147,12 @@ High-level flow:
 6. Export PDF.
 7. Delete temporary resume.
 
+### Resume-data caching
+
+JobOps caches successful Reactive Resume resume fetches in memory for 5 minutes.
+
+This reduces repeated API calls from settings loads, profile checks, project lookups, and PDF generation while still refreshing often enough for normal editing workflows.
+
 ### Per-job tracer links
 
 Before generating a PDF, each job can enable/disable tracer links.
@@ -208,6 +222,8 @@ curl -X POST "http://localhost:3001/api/jobs/<jobId>/generate-pdf"
 - Ensure the selected mode has credentials configured.
 - `v5`: set a valid API key.
 - `v4`: set email + password.
+- Invalid credentials block save and remain visible as an inline error until you edit the selected mode's credentials or URL.
+- Temporary Reactive Resume downtime shows an inline warning, but other settings can still be saved.
 - Save settings, then refresh resumes in the Reactive Resume section.
 
 ### No resumes appear in dropdown

docs-site/docs/features/settings.md

@@ -111,11 +111,14 @@ Defaults and constraints:
 
 - Configure a shared RxResume URL for cloud or self-hosted deployments
 - Configure v4 email/password or v5 API key in the same section
+- Invalid Reactive Resume credentials or other `4xx` config failures block the save and stay visible as an inline error
+- Temporary Reactive Resume downtime shows an inline warning, but the save still succeeds
 - Select a template/base resume
 - Configure project selection behavior:
   - Max projects
   - Must-include projects
   - AI-selectable projects
+- JobOps briefly caches successful Reactive Resume resume data to reduce repeated API calls across settings, profile, and PDF flows
 
 ### Tracer Links
 
@@ -215,6 +218,8 @@ curl -X POST "http://localhost:3001/api/backups"
 - JobOps resolves the RxResume URL in this order: the value saved in **Settings → Reactive Resume**, then the `RXRESUME_URL` environment variable (if set), and finally the public cloud default.
 - Open **Settings → Reactive Resume** and configure the shared RxResume URL if you use a self-hosted instance.
 - If you leave the URL blank, JobOps will fall back to `RXRESUME_URL` when it is configured; otherwise it uses the public cloud default.
+- Invalid credentials block the save and remain visible inline until you edit the selected mode's credentials or URL.
+- Temporary instance downtime shows a warning inline, but does not block unrelated settings updates.
 - Then refresh available resumes from the Reactive Resume section.
 
 ### RxResume projects look empty in the RxResume UI