docs(v5-next): backport v5 testnet connection details + evergreen doc fixes

[AztecBot]

v5-next docs backport covering the remaining survey candidates, the partial-notes docs from #23564, and the slashing-configuration rewrite from #24005 (now adapted to v5). Complements #24242 and #24243.

Files

v5 testnet connection details

• getting_started_on_testnet.md — NODE_URL → https://v5.testnet.rpc.aztec-labs.com, SPONSORED_FPC_ADDRESS → 0x261366…7880, dropped the stale "~36 seconds" block-time row.
• docs/docs/networks.md — testnet column → v5.0.0-rc.1 (rollup 4239416255, RPC, all L1/L2 addresses), verified against the live node's node_getNodeInfo. Mainnet column unchanged except 4.3.0 → 4.3.1.

slashing-configuration.md (from #24005, adapted to the v5 testnet)

Brings in #24005's structural rewrite (correct ejection mechanism, 72s slot math, grace period) and corrects the network-specific numbers to the v5 testnet config sourced from l1-contracts/script/deploy/DeployRollupForUpgradeV5.s.sol (Sepolia branch):

• slot 72s; round size 128 slots (4 epochs × 32) ≈ 2.6h
• slash amounts 100,000 / 250,000 / 250,000 (AZIP-16 full-stake preset) vs the old page's flat 2,000
• local ejection threshold 199,000 (so any single offense ejects a validator that joined at the 200,000 Activation Threshold) vs the old "98% / 3 slashes"
• execution delay 2 rounds (~5h) on testnet vs the old "28 rounds / ~3 days"

The old v5-next page was materially wrong for v5 (36s slots, 1%/3-strikes model). Caveat: these figures come from the v5 deploy config in-branch, not an on-chain read — the session's RPC proxy only serves mainnet, so I could not query the Sepolia rollup directly. Worth a confirmation against the live rollup before this merges.

Partial notes (from #23564, still open on next)

• partial_notes.md (expanded), partial_notes_as_payment_endpoints.md (new), docs-words.txt (unlinkable). All cross-links and the #include_code/references paths verified present on v5-next; v5-next's aip-20.md already documents the referenced API.

Evergreen

• community_calls.md — refreshed meeting times / links / calendar.
• ai_tooling.md — "never call bb directly" agent guidance (doc prose only).

Sources: v5 release-docs flow (7d6b320, f5fadef, 8bfd77d, b84af54, 80830d0), 8aed7c5/22393fe, 9ebff63, #24005 (slashing), #23564 (partial notes). No tracked issue is closed by this backport.