Task: Implement the Site Build feature

TASK-DESCRIPTION

Create: scripts/site-build.sh The script generates site.out/ from site.in/, and implements the requirements in prompts/features/01-site-build.md within the files in TASK-FILES.
Create: site.in/hello.txt The example page proves the build converts a page and substitutes its title.

TASK-OUTPUT

Provide the complete content of each created file, in the order listed in TASK-FILES, then the VERIFICATION: line.

TASK-CONTEXT

The authoritative requirements are prompts/features/01-site-build.md; the conventions are prompts/03-conventions.md. This task is the worked example for a task file: it is the shape every task in prompts/tasks/ follows.

TASK-FILES

Operation	Path
create	`scripts/site-build.sh`
create	`site.in/hello.txt`

TASK-VERIFY

Run: make test from the repository root.
Expected: exit status 0, and site.out/hello.html exists.

TASK-FEATURES

prompts/features/01-site-build.md

TASK-ACCEPTANCE

SITE-BUILD-R001
SITE-BUILD-R002
SITE-BUILD-R003
SITE-BUILD-R004
SITE-BUILD-R006
SITE-BUILD-R009
SITE-BUILD-R010
SITE-BUILD-R011

OUTPUT: the complete content of each created file in the order listed in TASK-FILES, ending with the VERIFICATION: line.