docs: remove TT SKY26b delivery date and mainnet schedule

[dmitrii-f-t27]

This repo's last commit predates the TT SKY26b cancellation, so nothing swept it. Two public surfaces still state a hard delivery date and a hard hardware dependency for a chip that was never fabricated.

In a token and mining protocol a stated date reads as a schedule commitment, which makes this the highest-consequence stale claim of the set.

• deployments/base-sepolia.md:51 — Mainnet deployment on Base L2 scheduled for Q2 2027 (post TT SKY26b silicon delivery, December 2026) → mainnet is not scheduled; it is gated on a silicon route; the order was cancelled and refunded; no route is currently selected.
• README.md:8 — Mining requires a physical TT SKY26b Trinity chip → restated as a design requirement, with the plain statement that no such chip exists.

The No chip, no TRI. Period. line is kept — with the correction above it now reads as the constraint it is.

Source for the cancellation: trinity-papers-ru PR #18, merged 2026-07-31 — Кристаллы не изготавливались, маршрут отменён, средства возвращены. Corroborated by tri-net/README.md:29 (Trinity silicon — NO ROUTE — no die exists, none is scheduled) and trinity-s3ai/README.md:39.

[dmitrii-f-t27]

@gHashTag — this is one of six PRs from a documentation and CI audit across the Trinity repos. Requesting your review here; I do not have permission to add you as a reviewer on this repo, hence the mention.

This one is the most time-sensitive of the set: the repo has not been touched since 2026-05-18, so it never saw the TT SKY26b cancellation. It still states a December 2026 delivery date and gates mining on a chip that was never fabricated. In a token protocol a stated date reads as a schedule commitment.

The full set:

• docs(readme): refresh three stale Metrics rows from their own commands tri-net#380 — three stale Metrics rows re-derived from the commands printed in their own rows
• Unbreak FPGA CI and correct two unbacked hardware claims t27#2081 — unbreak fpga-synthesis and fpga-bitstream, drop GREEN from three red README rows, remove two unbacked hardware figures
• fix(ci): make the three document gates actually run trinity-fpga#542 — make three document gates actually run (all three were vacuous or crashing)
• docs: reconcile catalog counts, LUT figures and device manifest against their sources trinity-fpga#543 — reconcile catalog counts, LUT figures and the device manifest against their sources
• docs(hardware): record TTSKY26b withdrawal in silicon_anchor §3 trinity-s3ai#52 — record the TTSKY26b withdrawal in silicon_anchor.md §3, which two README lines already cite as their evidence
• docs: remove TT SKY26b delivery date and mainnet schedule #2 — this one

Each PR body states what it does not fix as well as what it does. They are independent — merge or reject them separately.