docs: refresh add-aspire-existing-app guidance (#693)

* docs: tailor existing-app scenarios by toolchain

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* docs: keep existing-app update surgical

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* docs: expand AppHost API guidance

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* docs: sort AppHost API tables

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* docs: add TS addCSharpApp guidance

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* docs: restore TS API sort order

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* docs: update article package versions

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* docs: tab telemetry guidance

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* docs: streamline integrations guidance

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* docs: remove integrations section

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: exclude tablists from step spacing

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* docs: simplify existing-app conclusion

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* docs: move Docker Compose into scenarios

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* docs: reframe existing-app section intros

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

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Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: IEvangelist