feat(sync-snippets): switch to consumer-declared entrypoints

The CLI no longer asks each sdk.yaml which file in the consumer to
rewrite (see launchdarkly/sdk-meta#405); instead the consumer declares
its own list of search roots. Plumb that through:

- New required input `entrypoints` (newline-separated list of
  directories, relative to $GITHUB_WORKSPACE).
- Render step parses the input into individual `--entrypoint=` flags
  and passes them to `snippets render`.
- Empty / whitespace-only lines are tolerated and skipped; an empty
  list fails loudly.
- README + the in-action usage block updated to show the new shape.

Consumer wiring becomes:

    - uses: launchdarkly/gh-actions/actions/sync-snippets@main
      with:
        entrypoints: |
          static/ld/components/getStarted
        github-token: ${{ secrets.GITHUB_TOKEN }}

Author: kinyoklion

actions/sync-snippets/README.md

@@ -27,6 +27,8 @@ jobs:
       - uses: actions/checkout@v4
       - uses: launchdarkly/gh-actions/actions/sync-snippets@main
         with:
+          entrypoints: |
+            static/ld/components/getStarted
           github-token: ${{ secrets.GITHUB_TOKEN }}
 ```
 
@@ -35,13 +37,14 @@ jobs:
 1. Resolves the latest `snippets/vX.Y.Z` GitHub Release on `launchdarkly/sdk-meta` (override with `version:` if you need to pin or roll back).
 2. Downloads the platform-specific binary archive plus the cosign signature and certificate.
 3. Verifies the signature is keyless-signed by `launchdarkly/sdk-meta`'s `release-please` workflow on `main` via GitHub OIDC.
-4. Runs `snippets render --target=<adapter> --out=$GITHUB_WORKSPACE`. The binary embeds the canonical `sdks/` tree at build time — no separate snippet fetch.
+4. Runs `snippets render --target=<adapter> --entrypoint=<dir>...` with one `--entrypoint` flag per non-empty line of the `entrypoints:` input. The binary embeds the canonical `sdks/` tree at build time — no separate snippet fetch. The renderer walks each entrypoint recursively, picks up files with extensions it understands (`.tsx`/`.jsx`/`.ts`/`.js`/`.mdx`) that contain the `SDK_SNIPPET:RENDER:` sentinel, and skips junk dirs (`node_modules`, `.git`, `dist`, `build`, ...).
 5. Opens (or updates) a pull request with the rewritten files. If `render` produced no diff, the action exits 0 without opening a PR.
 
 ## Inputs
 
 | Name | Default | Description |
 |---|---|---|
+| `entrypoints` | (required) | Newline-separated list of consumer-checkout directories the renderer should walk for snippet markers. Paths resolve against `$GITHUB_WORKSPACE`. |
 | `version` | `latest` | Release tag to install (e.g. `snippets/v0.3.0`). `latest` resolves to the most recent published `snippets/*` release. |
 | `target` | `ld-application` | Adapter target. `ld-application` for gonfalon. Future targets (e.g. `ld-docs`) plug in here. |
 | `branch` | `chore/sync-sdk-snippets` | Branch the action commits the rendered diff to. |

actions/sync-snippets/action.yml

@@ -24,6 +24,8 @@ description: |
             - uses: actions/checkout@v4
             - uses: launchdarkly/gh-actions/actions/sync-snippets@main
               with:
+                entrypoints: |
+                  static/ld/components/getStarted
                 github-token: ${{ secrets.GITHUB_TOKEN }}
 
 inputs:
@@ -40,6 +42,16 @@ inputs:
       uses TSX render markers); future targets (e.g. `ld-docs`) plug in here.
     required: false
     default: 'ld-application'
+  entrypoints:
+    description: |
+      Newline-separated list of consumer-checkout directories the renderer
+      should walk for snippet markers. Paths are resolved relative to
+      $GITHUB_WORKSPACE (so a top-level `static/ld/components/getStarted` is
+      what gonfalon would pass). Each line becomes one `--entrypoint=` flag
+      to the CLI; the CLI walks each recursively, opens files with extensions
+      it understands (.tsx/.jsx/.ts/.js/.mdx), and skips junk dirs
+      (node_modules, .git, dist, build, ...).
+    required: true
   branch:
     description: 'Branch the action commits the rendered diff to.'
     required: false
@@ -173,12 +185,30 @@ runs:
 
     # 6. Render against the consumer checkout. `snippets` is now on $PATH.
     #    The CLI loads the canonical sdks/ tree from the binary's embedded FS
-    #    — no separate snippet sources to fetch.
+    #    — no separate snippet sources to fetch. Each line of the
+    #    `entrypoints:` input becomes one `--entrypoint=` flag (relative paths
+    #    resolve against $GITHUB_WORKSPACE).
     - name: 'Render snippets'
       shell: bash
+      env:
+        ENTRYPOINTS: ${{ inputs.entrypoints }}
       run: |
+        set -euo pipefail
         snippets version
-        snippets render --target='${{ inputs.target }}' --out="$GITHUB_WORKSPACE"
+        cd "$GITHUB_WORKSPACE"
+        args=()
+        while IFS= read -r line; do
+          # Strip surrounding whitespace; skip empty lines.
+          line="${line#"${line%%[![:space:]]*}"}"
+          line="${line%"${line##*[![:space:]]}"}"
+          [ -z "$line" ] && continue
+          args+=("--entrypoint=$line")
+        done <<< "$ENTRYPOINTS"
+        if [ ${#args[@]} -eq 0 ]; then
+          echo "::error::sync-snippets: at least one non-empty entrypoint must be provided"
+          exit 1
+        fi
+        snippets render --target="${{ inputs.target }}" "${args[@]}"
 
     # 7. Detect whether render touched anything. Empty diff means the consumer
     #    is already current; we exit cleanly with no PR.