docs: describe demo.script as an executable path

[codeforester]

Summary

Correct the Python manifest guide to describe demo.script as a relative executable file path, not a shell command string, and link the complete demo contract.

Issue

Fixes #2459

Validation

• git diff --check
• BASE_BASH_LIBS_DIR=/Users/rameshhp/work/base-bash-libs/lib/bash bats cli/bash/commands/basectl/tests/docs.bats (6 passing)

Dependencies

None.

[codeforester]

Code-review finding (cross-file consistency gap — not an inline comment because the file is outside this diff):

docs/command-reference.md lines 413-414 still groups demo.script with the trusted command-string surfaces, the same mischaracterization issue #2459 is about:

Manifest-declared commands are trusted project code. Base executes
test.command, build.targets.*.command, commands.*, demo.script, and
activate.source entries from the project root.

This PR correctly distinguishes demo.script in docs/python-manifest.md as a validated executable file path (must exist, be executable, and stay inside the project root — see cli/python/base_setup/demo.py::resolve_demo_script_path), not an arbitrary trusted shell command string. docs/command-reference.md still implies it's just another trusted command string executed like the others, with no such distinction. Consider applying the same clarification there (or a cross-reference to the corrected python-manifest.md section / project-demo-workflow.md) so the fix for #2459 is consistent across docs.

[codeforester]

Addressed the cross-file documentation consistency finding in b9d3a1c. docs/command-reference.md now distinguishes trusted shell command strings from the validated relative executable path in demo.script, links the complete Project Demo Workflow contract, and retains the review-before-running guidance.

The branch was rebased onto current main. Validation: docs.bats 6/6; targeted documentation/workflow tests 34 passed; Python compile, git diff --check, and the existing docs validation passed.

[codeforester]

Follow-up on current head b9d3a1c: the command reference now explicitly distinguishes command strings from demo.script executable paths, documents the project-root containment validation, and links the complete contract. The docs test suite passes.

[codeforester]

Addressed the remaining #2459 acceptance gaps in 7716ecfc:

• Added the demo.script contract row to docs/contracts.md, linked to the existing demo-resolution tests.
• Documented quoted demo.script paths containing spaces.
• Documented that compound shell logic belongs inside the executable script and that arguments after -- are forwarded unchanged.

Validation: tests/contracts/run.sh, focused docs/contract tests, and the docs BATS suite pass locally. Hosted checks for the new head are running.