Rewrite the roadmap for the 1.0 release line

[dannote]

The roadmap was last updated in July, and its framing still describes RustQ at 0.5 ("take RustQ from v0.5.x…"). Much of what it lists as open has since shipped:

• The lowering corpus exists and is gated by mix ci (rustq.corpus).
• Several projects dogfood RustQ beyond Skia.
• The docs are split into guides.
• Propagation inference covers almost everything: Skia's explicit unwrap! calls went from about 190 to 9, measured against its current master.

The roadmap also never mentioned the 1.0 release line, the compatibility policy, RustQ.Native, or source-derived codecs.

This rewrite covers:

• where RustQ stands at rc.11;
• the consumers and the RustQ version each one pins (only oxc_ex is within one release of the current RC);
• criteria for cutting 1.0.0, so that 1.0.0 is only a version change;
• remaining work, split into "before 1.0.0" and "1.x";
• the deliberate limits from the July adapter audit, kept so they aren't mistaken for missing inference.

It also drops the emoji status markers, the wave numbering, and the gap table.

It describes rc.11 features (Term.encoders_from_source and the keyword and literal-atom fixes), so it should merge after #1.