[agent-issue]: support weekday-only fuzzy schedules and cron parity

[krubenok]

Submission requirements

• I generated this issue with an agent that used .github/agents/ado-aw.agent.md.
• I reviewed the generated issue and confirm it is being filed directly in githubnext/ado-aw.

Problem summary

ado-aw 0.50.0 cannot express a fuzzy schedule that runs once per weekday. A workflow that should run Monday through Friday near 08:00 UTC-7 must currently choose between:

• schedule: daily around 08:00 utc-7, which also runs on Saturday and Sunday
• schedule: weekly on monday around 08:00 utc-7, which loses the required daily cadence

Azure Pipelines supports day-of-week ranges such as 1-5, so this is a parser and code-generation gap rather than a platform limitation.

gh-aw supports composable weekday forms including daily on weekdays, daily around 9am on weekdays, daily between 9:00 and 17:00 on weekdays, hourly on weekdays, and every 2h on weekdays. ado-aw's schedule documentation says its syntax is based on gh-aw's fuzzy schedule specification, but these forms are missing.

Minimum requested behavior:

on:
  schedule: daily on weekdays

The motivating workflow needs weekday filtering composed with fuzzy time and a UTC offset:

on:
  schedule: daily around 08:00 on weekdays utc-7

Reproduction details

Workflow source: .pipelines/agentic-workflows/slop-cop.md

1. Compile with ado-aw 0.50.0 using the supported workaround:

   on:
     schedule: daily around 08:00 utc-7

2. Inspect the generated .pipelines/agentic-workflows/slop-cop.lock.yml.

3. The generated Azure Pipelines cron is 15 15 * * *, which runs every day.

4. Try the supported single-day alternative:

   on:
     schedule: weekly on monday around 08:00 utc-7

5. It compiles, but runs only once per week.

Expected: a weekday modifier should preserve daily cadence and deterministic fuzzy timing, generating the equivalent of 15 15 * * 1-5 for the currently selected scattered minute.

Observed: the grammar accepts daily-every-day or weekly-on-one-day schedules, but cannot combine daily cadence, Monday-through-Friday filtering, fuzzy around timing, and a UTC offset.

Reference: https://github.github.com/gh-aw/reference/schedule-syntax/

Proposed next step

Extend FuzzySchedule and its parser and code generation to support on weekdays as a composable modifier.

Acceptance criteria:

• Support daily on weekdays.
• Support weekday filtering with daily around ..., daily between ... and ..., and utc±N offsets.
• Preserve deterministic scattering and emit Azure Pipelines day-of-week range 1-5.
• Add parser and cron-generation tests for weekday plus UTC-offset composition.
• Reject misplaced or conflicting modifiers with actionable compile-time errors.

For closer gh-aw parity, also support weekday modifiers on hourly and hour-interval schedules. A validated raw-cron schedule form would provide an escape hatch for schedules the fuzzy grammar does not yet cover.