feat: add observer install script and documentation

.editorconfig

@@ -0,0 +1,8 @@
+root = true
+
+[*.sh]
+shell_variant = bash
+indent_style = space
+indent_size = 4
+binary_next_line = true
+switch_case_indent = true

.github/workflows/checks.yml

@@ -0,0 +1,63 @@
+name: Checks
+
+on:
+  pull_request:
+  push:
+
+permissions:
+  contents: read
+
+jobs:
+  shell:
+    name: Shell checks
+    runs-on: ubuntu-24.04
+
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4
+
+      - name: Install ShellCheck
+        run: |
+          sudo apt-get update
+          sudo apt-get install --yes shellcheck
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: 1.24.x
+          cache: false
+
+      - name: Install shfmt
+        run: |
+          go install mvdan.cc/sh/v3/cmd/shfmt@v3.12.0
+          echo "$(go env GOPATH)/bin" >> "$GITHUB_PATH"
+
+      - name: Run shfmt
+        run: shfmt -d install tools
+
+      - name: Run ShellCheck
+        working-directory: install
+        run: |
+          shellcheck -x \
+            install-validator.sh \
+            install-observer.sh \
+            ../tools/generate-openresty-jwt.sh
+
+  markdown:
+    name: Markdown checks
+    runs-on: ubuntu-24.04
+
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+
+      - name: Run Prettier
+        run: npx --yes prettier@3.6.2 --check '**/*.md'
+
+      - name: Run Markdownlint
+        run: npx --yes markdownlint-cli2@0.21.0 './**/*.md' '#./.git/**'

.markdownlint-cli2.jsonc

@@ -0,0 +1,9 @@
+{
+  "config": {
+    "MD013": {
+      "line_length": 80,
+      "code_blocks": false,
+      "tables": false
+    }
+  }
+}

.prettierrc.json

@@ -0,0 +1,4 @@
+{
+  "printWidth": 80,
+  "proseWrap": "always"
+}

README.md

@@ -1,6 +1,7 @@
 # Seismic Node Operations
 
-Operational tooling and configuration for installing and running Seismic validator nodes.
+Operational tooling and configuration for installing and running Seismic
+validator and observer nodes.
 
 ## Validator installation
 
@@ -10,10 +11,55 @@ The interactive validator installer is located at:
 install/install-validator.sh
 ```
 
-For requirements, installation steps, persistent storage, MDBX notes, validator registration, service startup, OpenResty, and troubleshooting, see the **[Validator Installer and First-Start Guide](install/README.md)**.
+For requirements, installation steps, persistent storage, MDBX notes, validator
+registration, service startup, OpenResty, and troubleshooting, see the
+**[Validator Installer and First-Start Guide](install/README.md)**.
+
+## Observer installation
+
+The observer installer is located at:
+
+```text
+install/install-observer.sh
+```
+
+See the **[Observer Installer and First-Start Guide](install/OBSERVER.md)**.
+
+Generate short-lived bearer tokens for OpenResty-protected endpoints with:
+
+```text
+tools/generate-openresty-jwt.sh
+```
 
 The Summit internal-testnet genesis file is provided at:
 
 ```text
 internal_testnet_genesis.toml
 ```
+
+## Repository checks
+
+GitHub Actions checks shell scripts and Markdown through
+[`.github/workflows/checks.yml`](.github/workflows/checks.yml).
+
+Run the same checks locally from the repository root. ShellCheck must be
+installed; Go and Node.js with `npx` are also required.
+
+```bash
+go run mvdan.cc/sh/v3/cmd/shfmt@v3.12.0 -d install tools
+
+(
+  cd install
+  shellcheck -x \
+    install-validator.sh \
+    install-observer.sh \
+    ../tools/generate-openresty-jwt.sh
+)
+
+npx --yes prettier@3.6.2 --check '**/*.md'
+npx --yes markdownlint-cli2@0.21.0 './**/*.md' '#./.git/**'
+```
+
+Shell formatting is defined in [`.editorconfig`](.editorconfig). Markdown
+formatting and lint rules are defined in [`.prettierrc.json`](.prettierrc.json)
+and [`.markdownlint-cli2.jsonc`](.markdownlint-cli2.jsonc).