docs: update SDK pages after the next release, document Transfer project, refresh dashboard media #60

Three parts of the docs are left after #59.

after the SDK release (telemetry-dev/telemetry#146) merges:

• the sdk/typescript, sdk/python and plugin pages describe @telemetry-dev/sdk 0.2.2 and telemetry-dev 0.3.2: values are sent whole, records are cut at 16 MiB, and maxQueueBytes defaults to 64 MiB (fix(sdk): send each captured value whole telemetry#148)
• the experiment comment text on the experiment action page predates fix(sdk): fail the job for each failed experiment and give each matrix leg its own comment telemetry#154 and #157

missing page content:

• the project settings have a Transfer project action that no page covers

stale media (needs a seeded demo dashboard, not real usage):

• the trace-explorer recording and its poster, and dashboard-trace.png in the README, predate the Span ID row and the cost split by token class
• in telemetry-dev/stats, .github/preview.png has no Share stats button