refactor: reorganize skill numbering, remove obsolete skills, rename shared libs

- Rename: 00→80 claude-settings-optimizer, 88→79 dintel-skill-update,
  92→81 mac-optimizer, 93→82 tui-design-template
- Rename: dintel-shared → _dintel-shared (consistent with _ourdigital-shared)
- Remove: 61-gtm-manager, 62-gtm-guardian (obsolete), 99_archive
- Update all dintel-* skill refs (114 occurrences across 31 files)
- Sync README.md, CLAUDE.md, AGENTS.md with new structure

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

custom-skills/73-dintel-quotation-mgr/README.md

@@ -15,7 +15,7 @@ Quotation Manager -- the most complex skill in the D.intelligence Agent Corps. U
 | **Scope Agent** | Analyzes client requirements, maps to service modules (A1--G4) |
 | **Resource Agent** | Estimates effort hours, timeline, team allocation |
 | **Pricing Agent** | Calculates pricing using module rates, package discounts, discount policies |
-| **Output Generator** | Produces branded Excel .xlsx file using `dintel-shared/src/dintel/excel.py` |
+| **Output Generator** | Produces branded Excel .xlsx file using `_dintel-shared/src/dintel/excel.py` |
 
 ## Directory Structure
 
@@ -35,8 +35,8 @@ Quotation Manager -- the most complex skill in the D.intelligence Agent Corps. U
 
 ## Key References
 
-- Brand Guide: `../../dintel-shared/src/dintel/brand.py`
-- Excel utilities: `../../dintel-shared/src/dintel/excel.py`
+- Brand Guide: `../../_dintel-shared/src/dintel/brand.py`
+- Excel utilities: `../../_dintel-shared/src/dintel/excel.py`
 - Service Map: `/Users/ourdigital/Documents/D.intelligence Service Package/00_SERVICE-MAP.md`
 - Pricing Packages: `/Users/ourdigital/Documents/D.intelligence Service Package/06_PRICING-PACKAGES.md`