feat(workflows): expose workflow source directory to steps (#3469)

* feat(workflows): expose workflow source directory to steps (#3467)

Propagate WorkflowDefinition.source_path to steps via
{{ context.workflow_dir }} in template expressions and
SPECKIT_WORKFLOW_DIR env var for shell steps. The original
source directory is persisted in state.json so resume
restores the correct value instead of the run-directory copy path.

Closes #3467

Assisted-By: 🤖 Claude Code

* fix: apply bot review suggestions (#2)

Applied fixes from bot review comments:
- Comment #3563319058: prevent stale SPECKIT_WORKFLOW_DIR leak from parent env
- Comment #3563319094: use cross-platform Python one-liner instead of printenv
- Comment #3563319103: add monkeypatch.delenv for deterministic env var test
- Comment #3563319116: same env leak fix as #3563319058

Assisted-By: 🤖 Claude Code

* fix: use YAML single-quotes and forward-slash paths for Windows CI (#2)

sys.executable on Windows returns backslash paths (D:\a\...) which YAML
double-quoted strings interpret as escape sequences. Switch to
single-quoted YAML strings and normalize paths with replace("\\", "/").

Assisted-By: 🤖 Claude Code

* fix: resolve workflow_dir to absolute path and add installed-by-ID test (#3469)

Applied fixes from bot review comments:
- Comment #3563382853: resolve source_path before taking parent to ensure absolute paths
- Comment #3563382864: add test for installed-by-ID workflow_dir semantics

Assisted-By: 🤖 Claude Code

* docs: document context.workflow_dir and SPECKIT_WORKFLOW_DIR

Add reference documentation for the new workflow_dir runtime value in
both workflows/README.md and docs/reference/workflows.md so workflow
authors can discover the feature and its semantics.

Assisted-By: 🤖 Claude Code

* fix: clarify installed workflow_dir is an absolute path (#3469)

The documentation for context.workflow_dir described the installed-by-ID
case as ".specify/workflows/<id>/" which appears relative, contradicting
the "resolved absolute path" semantics. Clarified that it is the absolute
path to the installation directory.

Assisted-By: 🤖 Claude Code

* fix: apply bot review suggestions (#3469)

Applied fixes from bot review comments:
- Comment #3580005128: Quote sys.executable in shell step env var test
- Comment #3580005174: Quote sys.executable in no-env-var test

Assisted-By: 🤖 Claude Code

* fix: apply bot review suggestions (#3469)

Applied fixes from bot review comments:
- Comment #3587146944: Quote interpolated workflow_dir path in example

Assisted-By: 🤖 Claude Code

workflows/README.md

@@ -348,6 +348,7 @@ current run:
 | Variable | Description |
 |----------|-------------|
 | `context.run_id` | The current workflow run id (the same value Spec Kit prints as `Run ID:` at the end of `workflow run`). Auto-generated runs are 8-character hex from `uuid4`; operator-supplied ids may be any alphanumeric string with hyphens or underscores. Empty string outside a run context. |
+| `context.workflow_dir` | The resolved absolute path to the directory containing the workflow source file. For file-loaded workflows this is the parent directory of the YAML file; for installed-by-ID workflows it is the absolute path to the installation directory (e.g. `<project>/.specify/workflows/<id>/`); for string-loaded workflows it is an empty string. On resume the original source directory is preserved from the first execution. |
 
 ```yaml
 # Stamp telemetry events with the run id for cross-system join.
@@ -365,6 +366,11 @@ current run:
   command: speckit.specify
   input:
     args: "{{ context.run_id }}"
+
+# Reference a sibling file shipped alongside the workflow definition.
+- id: apply-config
+  type: shell
+  run: 'cp "{{ context.workflow_dir }}/defaults.yml" ./config.yml'
 ```
 
 ## Input Types
@@ -445,6 +451,7 @@ specify workflow catalog remove <index>
 | Variable | Description |
 |----------|-------------|
 | `SPECKIT_WORKFLOW_CATALOG_URL` | Override the catalog URL (replaces all defaults) |
+| `SPECKIT_WORKFLOW_DIR` | Set automatically for shell steps; contains the resolved absolute path to the workflow source directory (same value as `{{ context.workflow_dir }}`). Not set when the workflow has no source path (string-loaded workflows). |
 
 ## Configuration Files