The author does not say that Bergson's conclusion is Proust's technique. She says that Proust "channeled this conclusion into" his technique: that is, that Proust's familiarity with Bergson's philosophical posture is evident in the characteristic form of Proust's work.
Likewise, the definition you provide does not say that "literary technique" is literary analysis. It says that the technique is something actually present in a literary work which can be identified by literary analysis.
Proust is beyond my expertise, so I can't provide concrete examples of Bergson's philosophy "channeled into" Proust's work. But it happens that I wrote a paper in grad school which employed Bergson's ideas on the other end, in literary analysis. Briefly, I argued that unusual elements of Shakespeare's technique in Macbeth—specifically, the constant slipping between flexible iambic pentameter and mechanical trochaic tetrameter, and the construction of the work in long sequences of deliberately overlapping rather than sequential scenes—could be understood to reflect a 'Bergsonian' contrast between the sense of time as durée, something to be lived through and intuited, and the 'mechanical' sense time as something which can be mathematically partitioned and measured. ... Of course there's no question of Shakespeare's having been influenced by Bergson! —but it illustrates how a philosophical posture can be embodied in a work of art, and detected there, without in any way identifying either the creative or the critical activity with the philosophic activity.