chore: consolidate documentation — delete status/fix/progress cruft

Before: 335 tracked .md files; top level had 14 README-like docs;
docs/ contained ~234 files, most of them auto/LLM-generated status
reports (ALL_*_COMPLETE*, *_FIX*, DEPLOYMENT_*_FINAL*, etc.).

After: 132 tracked .md files. Repo now has exactly five top-level
docs: README.md, QUICKSTART.md, RUNBOOK.md, CONTRIBUTING.md,
CHANGELOG.md (moved up from docs/).

Keeper philosophy in docs/:
- API, CCIP (ops + security + receiver/router refs), Chainlist refs,
  compliance, deployment (guides not status), database connection,
  legal compliance, metamask integration, production checklist,
  tiered-architecture implementation/setup, reusable-components plan,
  token-mechanism doc, wrap-and-bridge operational reference, plus
  docs/specs/** and docs/api/ / docs/openapi/ trees.

Deleted (git history preserves provenance):
- All 'ALL_*_COMPLETE*' / '*_FIX*' / '*_FIXED*' / '*_FINAL*' /
  '*_STATUS*' / '*_PROGRESS*' / '*_SUMMARY*' files.
- BLOCKSCOUT_*_FIX / _CRASH / _INITIALIZATION / _SCHEMA / _YAML /
  _SKIP / _NEXT_STEPS / _START_AND_BUILD / _DATABASE_CREDENTIALS
  (the last contained passwords).
- CCIP_IMPLEMENTATION_* / CCIP_CURRENT_STATUS / CCIP_GAP_*
  (gap analyses are not a sustained reference).
- NPMPLUS_CREDENTIALS_GUIDE.md (contained creds).
- LETSENCRYPT_CONFIGURATION_GUIDE.md (contained creds; will be
  re-introduced as runbook content post-secrets-scrub).
- docs/diagnostic-reports/, docs/feature-flags/ (run-time artifacts).

README.md: dead links (START_HERE, README_DEPLOYMENT, COMPLETE_DEPLOYMENT,
DEPLOYMENT_COMPLETE_FINAL) replaced with links to the five canonical
top-level docs + docs/ index.

docs/SUBMODULE_SETUP.md

@@ -1,98 +0,0 @@
-# Setting Up Explorer as Git Submodule
-
-## Current Status
-
-The explorer monorepo has been created and initialized as a git repository. It's currently configured as a local submodule.
-
-## Converting to Remote Repository (Recommended)
-
-To make the submodule work properly with remote repositories:
-
-### Step 1: Create Remote Repository
-
-1. Create a new repository on GitHub/GitLab/etc:
-   - Name: `chain-138-explorer`
-   - Description: "Blockchain explorer for ChainID 138"
-
-### Step 2: Push Explorer to Remote
-
-```bash
-cd explorer-monorepo
-
-# Add remote
-git remote add origin https://github.com/yourusername/chain-138-explorer.git
-
-# Push to remote
-git push -u origin main
-```
-
-### Step 3: Update Submodule Reference
-
-In the parent project:
-
-```bash
-cd /home/intlc/projects/proxmox
-
-# Update .gitmodules
-cat > .gitmodules <<EOF
-[submodule "explorer-monorepo"]
-	path = explorer-monorepo
-	url = https://github.com/yourusername/chain-138-explorer.git
-EOF
-
-# Update submodule reference
-git submodule sync
-git add .gitmodules
-git commit -m "Update explorer submodule to use remote repository"
-```
-
-## Using the Submodule
-
-### Clone Parent Project with Submodule
-
-```bash
-git clone <parent-repo-url>
-cd proxmox
-git submodule update --init --recursive
-```
-
-### Update Submodule
-
-```bash
-# Update to latest
-cd explorer-monorepo
-git pull origin main
-cd ..
-git add explorer-monorepo
-git commit -m "Update explorer submodule"
-```
-
-### Work on Submodule
-
-```bash
-cd explorer-monorepo
-# Make changes
-git add .
-git commit -m "Your changes"
-git push origin main
-cd ..
-git add explorer-monorepo
-git commit -m "Update submodule reference"
-```
-
-## Local Development (Current Setup)
-
-If keeping it as a local submodule:
-
-1. Work directly in `explorer-monorepo/`
-2. Commit changes normally
-3. The parent project will track the submodule state
-
-## Benefits of Monorepo Structure
-
-1. **Organization**: Clear separation of concerns
-2. **Versioning**: Independent versioning of explorer
-3. **Reusability**: Can be used in other projects
-4. **Deployment**: Standalone deployment scripts
-5. **Documentation**: Self-contained documentation
-