docs(roadmap): convert dated timeline to non-dated capability progression and add methodology

[Shards-inc]

Motivation

• Remove unsupported calendar claims from the roadmap so public statements are evidence-backed or explicitly non-dated.
• Preserve the intended sequencing and deliverables while avoiding date-specific assertions that lack commit-level verification.

Description

• Reworked docs/roadmap/ROADMAP.md from a calendar-based “Release Timeline” into a non-dated Capability Progression section.
• Replaced explicit quarter/month targets and per-phase dates with progression-oriented labels (e.g., Progression Slot) and converted milestone dates into ordered sequence entries.
• Updated header Last Updated to a non-dated phrase and replaced the Changelog area with a Methodology statement and Revision Notes.
• Added one-line methodology declaring that timeline language is intentionally non-dated and that dates are retained only when directly verifiable from commit metadata.

Testing

• Ran a repository diff check and found no issues.
• Documentation-only change; no unit or integration tests were required for this modification.

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[chatgpt-codex-connector]

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