FR: Make it possible to set title text, to display in the orange bar at the top.

User story

I often have several experiments running in parallel, with a tensorboard tab for each. hen tabbing between them to compare results, it's very hard to keep track of which experiment's results I'm looking at.

Proposed solution

Allow the user to programmatically set some arbitrary but short (one line) title text, to be displayed in the orange bar at the top of that experiment's tensorboard page.

Comparison to other feature requests

This request differs from #46 and #194 in that I want a short, human-scannable title at the top, rather than a comprehensive readout of metadata (hyperparams in #46, and metadata in #195). Those are also are good FRs that solve real problems, but they wouldn't serve the purpose here of being a short, readable title, easily scanned by a human when tabbing between experiments.

This also differs from #210, which concerns itself with tagging with metadata, which must be machine-readable, whereas here the focus is on having a human-scannable piece of arbitrary text at a prominent location of the tensorboard page.

No files or tests are named. Start by locating the TensorBoard page entry point that renders the orange top bar and the existing programmatic configuration APIs; then determine how a short title can flow to that UI. Done means users can set one-line arbitrary text programmatically and see it prominently on the corresponding experiment page.