refactor(frontend): eliminate backdrop-blur throughout codebase

Remove all instances of backdrop-blur effect (14+ occurrences) to simplify visual design
and eliminate signature 2023-2024 AI aesthetic tell. Components now use solid backgrounds
and borders for hierarchy and affordance instead of decorative blur.

Affected:
- BottomNav: solid bg-slate-950, clean border
- AdminOverlay: removed overlay blur
- Admin managers (Identity, Database, AI, Category, LDAP): removed glass-card aesthetic
- Modals (IdentityCheck, Scanner, AIOnboarding): removed decorative blur
- Page layouts (home, inventory, logs): removed modal backdrop blur
- globals.css: removed glass-card utility

Build: passes with zero errors. Bundle sizes unchanged.

Simplification improves: clarity, perceived intentionality, removes AI aesthetic tells.

AI_RULES.md

@@ -51,6 +51,17 @@ This is the **Single Source of Truth** for ALL AI agents. Refer to [PROJECT_ARCH
   5. Run `./export_prod.sh`.
   (Always use `python3 scripts/save_version.py`).
 
+## 6. Implementation Completion
+- All code modifications MUST be committed in git before the task is considered finished. `VERSION.json` must be updated on EACH commit.
+- **MANDATORY GIT RULE:** Never push to remote unless explicitly requested by the user. Only commit locally with proper messages. Always assume the user will handle all `git push` operations. If a task requires pushing, ask for explicit permission first.
+- **MANDATORY GIT RULE**: NO AI is allowed to write in git commits that it is the author or co-author (e.g., DO NOT add texts like `Co-Authored-By: AI...`). Commits should only contain technical messages.
+- After finishing an entire job, end your final response on a separate line exactly with:
+  ```
+  ---
+  ✓ Done.
+  ```
+- Do not provide unnecessary summaries of the code.
+
 ---
 
 ## END OF SESSION PROTOCOL