Add development-scripts agent skill

Ports generic-scripts-module-v1 into a routed skill: module anatomy, shared
loggers/base modules, Taskfile integration, workflows, and pattern decisions.

Fixes a latent defect in the loggers example that silenced all logging in the
module scaffold: loggers/lib/--index-api.sh now sources --env-vars-reader.sh,
and the reader preserves already-exported values so caller overrides still win.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

README.md

@@ -1 +1,55 @@
-# development-scripts
+# development-scripts
+
+Agent Skill for shell script modules under a repository's `.scripts/` directory — the
+`api/` + `lib/` split, the `--index.sh` bootstrap chain, Taskfile integration, and the shared
+`loggers` and `base` foundation modules.
+
+## Layout
+
+```text
+development-scripts/
+├── SKILL.md                          # Entry point — routing, anatomy, naming, runtime flow
+├── references/
+│   ├── module-anatomy.md             # Reader, validator, index files, implementations, wrappers
+│   ├── shared-modules.md             # loggers and base, and the logging bootstrap rule
+│   ├── taskfile.md                   # Module and root Taskfile integration
+│   ├── workflows.md                  # Create, change, validate
+│   └── module-patterns.md            # Module type and dependency decision guide
+└── assets/
+    ├── module-example-v1/            # Scaffold to copy for a new module
+    ├── loggers/                      # Working reference implementation
+    └── base/                         # Working reference implementation
+```
+
+## The model
+
+```text
+<target-repository>/
+  Taskfile.yml
+  .scripts/
+    <module>/
+      api/                 # public command wrappers — what users run
+      lib/                 # implementation functions — what the code calls
+      Taskfile.yml         # only when exposed through task
+```
+
+Commands run from the repository root:
+
+```bash
+./.scripts/<module>/api/<command>.sh --dry-run
+task <module-alias>:<task-name> -- --dry-run
+```
+
+Every source path is repository-root-relative, and the bootstrap chain — reader, then
+validator, then API index — guarantees an implementation function sees a fully-prepared
+environment.
+
+## Deploy
+
+```bash
+cd ../skill-manager/scripts
+task deploy -- --skill-dir="$(cd ../../development-scripts && pwd)"
+```
+
+Built with the `skill-manager` skill, following the
+[agentskills.io specification](https://agentskills.io/specification).